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 All Los Angeles Unified School District campuses will reopen Wednesday, officials announced, following an unprecedented districtwide closure Tuesday after the LAUSD received a threat of violence that law enforcement agencies ultimately determined was "not credible." 
 
 "We believe that our schools are safe," Steve Zimmer, president of the LAUSD board, said early Tuesday evening at a news conference attended by Mayor Eric Garcetti, LAPD Chief Charlie Beck and Los Angeles County Sheriff Jim McDonnell. 
 
 "Some have used words that I think are inappropriate like 'hoax' and other things" to describe the incident, Garcetti said. "Whether it's criminal mischief, whether it's somebody testing vulnerabilities of multiple cities, we still do not know enough to say definitively." 
 
 The threat against the nation's second-largest school district was sent via email to a school board member Monday evening and was traced back to an IP address in Frankfurt, Germany, according to LAUSD spokeswoman Ellen Morgan. 
 
 Officials announced the districtwide closure shortly before 7 a.m. Tuesday. 
 
 The Los Angeles Police Department was notified about a "specific" threat late Monday night that had been sent to a number of school board members, Beck said during a mid-morning news conference. 
 
 The implied threat was "explosive devices," "assault rifles" and "machine pistols," according to Beck. 
 
 Garcetti, speaking at the same morning news conference as the police chief, added that the message included a number of forms of violence and weapons, and stated that "things were already in place to bring that violence about." 
 
 Early on in the investigation, the city's Emergency Operation Center was activated at its lowest level, the mayor said. 
 
 The threat -- also made against New York City schools -- was deemed a "hoax or something designed to disrupt school districts in large cities" in a preliminary assessment, according to Rep. Adam Schiff, a Democrat who represents parts of L.A. and is on the House Intelligence Committee. 
 
 Beck later defended the decision to close schools. 
 
 "When parents make their determination about the decisions that were made today," he said, "I would ask them to look at it this way: If you knew what the superintendent and the school board knew at 5:30 this morning, when the decision had to be made, would you have sent your child to school?" 
 
 "Every parent I've asked said, no, of course not," he said. 
 
 In an interview with KTLA, Karlee Parrish, an LAUSD parent, expressed support for Tuesday's closure. 
 
 "If there's anything like that is ever even a potential threat, I would want them to cancel all schools," she said. 
 
 Tom Torlakson, state Superintendent of Public Instruction, noted the technical possibility that the LAUSD would not receive about $29 million in funding due to the "loss of ADA," or average daily attendance, caused by the shutdown. 
 
 "I have the power, as superintendent, in emergencies, to recommend that the district be made whole," he said. "We're nearly 100 percent certain that we can take the steps to restore those funds to the district." 
 
 Although the email originated from an IP address in Germany, the source of the threat was unknown, according to Beck. He said he believed the threat came from much closer than Europe. 
 
 School officials initially referred to the threat as "credible." After a 12-hour investigation, however, the LAPD, LAUSD, Los Angeles County Sheriff's Department and FBI "have determined that this is not a credible threat," Beck said. 
 
 A similar threat was made against New York City's school system on the same day, according to New York Police Commissioner Bill Bratton. He described the email that the superintendent of his city's school system received as "almost exactly the same" as the one LAUSD officials were sent. 
 
 New York police believe the threat in their city to be a “hoax," said Bratton, a former LAPD chief. 
 
 In a live phone interview with KTLA, Rep. Brad Sherman said he had reviewed the emails. The one directed at New York schools included a claim that 138 people were involved, while the one sent to L.A. stated 33 people were involved. 
 
 "The New York email lacked credibility. There were certain parts of the Los Angeles email that are not credible," Sherman said. 
 
 “The purpose of terrorism is not necessarily to blow things up, and to cause casualties, but to create fear," said the congressman, who represents part of the San Fernando Valley. "This email did just that at very little cost to whoever sent it.” 
 
 Earlier, Superintendent Ramon Cortines described the nature of the threat as "unspecified." It was initially characterized as a "terror threat" by another LAUSD official. 
 
 Calling the threat "rare," Cortines said the threat was directed to "students at schools." He added it was made to "many schools," but did not identify any by name. 
 
 Officials later clarified the threat had been made to all schools. 
 
 The superintendent stated that he made the decision to close all campuses after consulting with Zimmer and Los Angeles School Police Department Chief Steven Zipperman. 
 
 Cortines had the full support of Garcetti, who said that while the decision to close the schools was not his to make, "it is mine to support as mayor." 
 
 All the schools were being thoroughly searched to ensure the grounds were "safe for children," according to Cortines. 
 
 "I've asked the plant managers to walk the school, and if they see anything that is out of order to contact the police," Cortines said. 
 
 The LAPD -- which has taken the lead in the investigation -- and the Sheriff's Department assisted school police in search operations of all campuses. 
 
 A number of police patrol cars and SWAT vehicles were seen in the vicinity of local schools in the hours after LAUSD disclosed the threat, video from Sky5 showed. 
 
 School bus service was canceled for the day. All LAUSD students with a valid student ID were able to ride Metro services for free Tuesday. 
 
 Other districts in Southern California reported receiving no threats to their schools, and were operating their campuses normally. Some charter, private and Catholic schools closed. 
 
 Cortines felt it was important to take the precaution "based on what has happened recently, and what has happened in the past," he said, alluding to the recent mass shooting in San Bernardino, which was being investigated by the FBI as an "act of terrorism." 
 
 The Dec. 2 attack at the Inland Regional Center left 14 people dead and 22 others injured. 
 
 “Whether this pans out as something that could have happened or not … I do not want people to say – because sometimes things don’t result in a shooting, or don’t result in a foiled plot – to not speak up and to not speak out," Garcetti initially said, while the threat was being analyzed. “If you see something, say something.” 
 
 As law enforcement personnel walked through all the campuses looking for anything suspicious, schools were closed Tuesday out of an abundance of caution and to ensure the safety of students, according to the school police chief. 
 
 A number of steps were taken before the schools were cleared to reopen, including gathering information obtained by LAPD and the Sheriff's Department from the campus sweeps, Zipperman stated. 
 
 The superintendent and school board members were then briefed and made a final determination based on the collected evidence on whether classes would be in session on Wednesday. 
 
 "We will not do that until we are completely satisfied that we have taken every measure possible to ensure the safety of our students," Zipperman said at the initial news conference. 
 
 In the meantime, parents and guardians were urged in the morning hours to keep their kids home from school on Tuesday. 
 
 Anyone who had already dropped their child off was asked to pick them up. Proper ID was required and checked upon picking students up, school officials said. 
 
 LAUSD serves more than 640,000 students throughout the Los Angeles area and in multiple nearby cities, according to its website. The district is comprised of 900 school and 187 public charter schools. 
 
 After a brief outage, an information hotline was working again for parents with questions: 213-241-2064. 
 
 KTLA's Melissa Pamer, Alberto Mendez and Irving Last contributed to this story. 
 
 LAUSD has issued a guidance in order to help schools "restore calm." Click here for more information. 
 
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 Please enable Javascript to watch this video ||||| The public school systems in New York and Los Angeles both received bomb threats today, but only one city took it seriously. So why did 640,000 California kids get the day off while New York’s youths had to spend a lovely 60-degree day in class? Credulity. 
 
 Though neither email has been made public, it appears both school systems received similar—if not identical—emails, threatening a multi-pronged, jihadi attack on multiple schools, using bombs and nerve gas. But there were plenty of details to indicate the threat was a hoax. Among them: 
 
 Both emails were sent by Cockmail—an email host affiliated with the gutter image board 8chan that boasts decidedly non-halal domains like “nigge.rs,” “horsefucker.org,” and “goat.si,” as well as multiple variations on the phrase, “dicksinmyan.us.” (The NYPD has since subpoenaed “Cock.li Email Hosting,” and California state Rep. Brad Sherman confirms the LA email came from a “pornographic” address.) 
 
 
 
 Both emails spelled the word “Allah” with a lowercase “a” 
 
 The author of the Los Angeles email, at least, claimed to be a victim of bullying. 
 
 “There was nothing credible about the threat. It was so outlandish,” New York Mayor Bill de Blasio said at a news conference Tuesday. 
 
 
 
 “It is very easy in hindsight to criticize a decision based on results the decider could never have known,” LA Police Chief Charlie Beck said at a different news conference Tuesday. 
 
 
 
 Perhaps. But it’s also apparently very easy to shut down a school—or many schools, in a major American city— by pretending to be an ISIS fighter using an email with the word “cock” in it. ||||| Officials release email threat to HISD schools 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Photo: Cody Duty Image 1 of / 4 Caption Close Image 1 of 4 At the Arabic Immersion School in north Houston, a police car blocked one entrance, and an officer patrolled the sidewalk on the other side of the campus in the wake of terror threats across the country. Dec. 17, 2015 less At the Arabic Immersion School in north Houston, a police car blocked one entrance, and an officer patrolled the sidewalk on the other side of the campus in the wake of terror threats across the country. Dec. ... more Photo: Cody Duty Image 2 of 4 At the Arabic Immersion School in north Houston, a police car blocked one entrance, and an officer patrolled the sidewalk on the other side of the campus in the wake of terror threats across the country. Dec. 17, 2015 less At the Arabic Immersion School in north Houston, a police car blocked one entrance, and an officer patrolled the sidewalk on the other side of the campus in the wake of terror threats across the country. Dec. ... more Photo: Cody Duty Image 3 of 4 
 
 The L.A. school system received a similar threat earlier this week. Keep clicking to see photos from the scare that closed schools. less Houston Independent School District Superintendent Terry Grier said students' safety is the district's No. 1 priority. HISD received a threat targeting unnamed campuses. 
 
 The L.A. school system received a similar ... more Houston Independent School District Superintendent Terry Grier said students' safety is the district's No. 1 priority. HISD received a threat targeting unnamed campuses. Photo: Brett Coomer, Staff Image 4 of 4 A lock holds the gate shut at Edward Roybal High School in Los Angeles, on Tuesday morning, Dec. 15, 2015. All schools in the vast Los Angeles Unified School District, the nation's second largest, have been ordered closed due to an electronic threat Tuesday. less A lock holds the gate shut at Edward Roybal High School in Los Angeles, on Tuesday morning, Dec. 15, 2015. All schools in the vast Los Angeles Unified School District, the nation's second largest, have been ... more Photo: Richard Vogel, AP Officials release email threat to HISD schools 1 / 4 Back to Gallery 
 
 Houston Independent School District leaders on Thursday disclosed additional details about an email sent to Superintendent Terry Grier and others threatening widespread violence at unnamed campuses, similar to messages sent earlier this week to Los Angeles and New York that were considered hoaxes. 
 
 The email was not sent from Houston and was "over the top" based on "type of weapons and explosives that were going to be used," HISD Police Chief Robert Mock said. 
 
 The message, he said, was "very similar" to the one posted in California, and district officials are seeking FBI approval to release it. 
 
 At least one change had been made to an email earlier to another district, with "Allah" capitalized, Mock said. 
 
 The email was sent Wednesday night to about half a dozen HISD employees, including the generic email for the superintendent, Mock said. The message was forwarded to the police chief at 8:17 p.m., chief of staff Jason Spencer said, and officers began meeting while Grier called superintendents across the country. 
 
 HISD released the email Thursday afternoon: 
 
 Hello there. There is something you should know about, taking place 
 
 tomorrow of 12/17/15, Thursday. 
 
 My story starts here. I have been bullied every day here, in one of the 
 
 district high schools. Just because, I am 'different'. I turned to 
 
 religion, to solve my problems, and found faith and comfort in Allah. He 
 
 has helped me through a lot. So now, I must help him. He has called upon 
 
 me and my fellow comrades to take action against you blasphemers and 
 
 non-believers. You have denied Allah for too long. My 46 Jihad 
 
 affiliates and I are going to unleash an massacre of epic proportion, 
 
 targeting every single school and student in the district. We have an 
 
 assorted collection of Kalashnikov rifles, MG240 Light machine guns, RPG 
 
 Launchers, .50 Cal Sniper rifles, hand grenades, and to top it off: 
 
 suicide vests. We have already planted napalm, propane, and pressure 
 
 cooker explosives in multiple schools. They are set to go off in places 
 
 that will cause maximum structural damage to each building: for maximum 
 
 casualty. First responders will be in for quite the surprise, as we have 
 
 highly trained sniper forces straight from Ar Raqqa. We will fight for 
 
 our cause tomorrow, and all students in every school in the entire 
 
 district will be slaughtered for their blasphemy and unbelief in the one 
 
 true God, Allah. You will no longer get away with your dishonesty to our 
 
 prophet. 
 
 Allah has called upon us: 
 
 Quran (3:56) - "As to those who reject faith, I will punish them with 
 
 terrible agony in this world and in the Hereafter, nor will they have 
 
 anyone to help." 
 
 You will no longer deny the wrath of Allah. He has sent us to serve his 
 
 holy army. 
 
 My name is (name redacted). You may not know this name now, 
 
 but my name will be known to everyone. I will be known as the one man 
 
 who truly saved this earth. For Allah. 
 
 And if you think you will stop us, by canceling schools, or perhaps, 
 
 adding security, it will not help. 
 
 If school is canceled, then there will be bombings regardless of whether 
 
 students are there or not, and mass shootings will be taken to the 
 
 streets. If security is stepped up, for tomorrow's fatwa, it will not 
 
 help. We will take out any police and other security by any means 
 
 necessary, even if we go down with them. 
 
 الله أكبر 
 
 ‏محمد رسول الله 
 
 The similarity of the email to the one sent to various districts was a major reason that HISD officials deemed it not credible and decided to keep schools open Thursday, Mock said, adding that he sent his own children. 
 
 "It's not sophisticated. It's an email," Mock said. "Not to downplay it, a threat is a threat." 
 
 HISD called in all of its police officers on overtime Thursday morning to patrol schools, and tapped several other agencies, including the Houston, Bellaire and West University police departments, according to district spokeswoman Holly Huffman. 
 
 The district maintenance staff also checked every school, Huffman said. 
 
 "Everything's been normal this morning," said Mock. 
 
 District officials told parents in an automated phone call around 10 p.m. Wednesday that they had received a threat that they did not deem the threat credible and that schools would be open Thursday. A call with updates went out around 11 a.m. Thursday. 
 
 "As a precautionary measure," the original message said, "law enforcement officers are currently conducting random sweeps of school district buildings to ensure student safety." 
 
 At the Arabic Immersion School in north Houston, a police car blocked one entrance, and an officer patrolled the sidewalk on the other side of the campus Thursday morning. 
 
 "There's no concern," said one man dropping off a student, declining to give his name. 
 
 Erika Carrillo said she received the warning message from HISD Wednesday night, but brought her 6-year-old son to school Thursday morning to maintain routine and not make the boy nervous. 
 
 "I don't want to live scared. I need to live normally," she said, as she walked her son into the magnet school. 
 
 At Pershing Middle School in southwest Houston, Antonio Toledo dropped off his daughter, saying he wasn't worried about the threat because it had no specific details. 
 
 Sam Olivares, bringing her daughter to Pershing Middle School at 3838 Blue Bonnet, said she hadn't heard about the threat. But even if she had known about it, her three children would still have come to school. 
 
 "I'm one of the ones who believe that it shouldn't scare you away," said Olivares, who has a daughter at the High School for the Performing and Visual Arts and a son at Bellaire High School. "To me, that's their entire point -- to get you to be afraid." 
 
 Patricia Lopez, a fifth grade teacher at Mark Twain Elementary next door to Pershing, was in the process of taking one daughter to Lanier Middle School and another to Lamar High School. 
 
 "It's disturbing because we can't take any threat lightly," Lopez said, noting that public attention to the issue makes children fearful, which saddens her as a parent and educator. 
 
 "The district's responsibility is obviously the safety of the community, but the way social media exploits it makes it incredibly hard to keep things calm," Lopez said. "I'm assuming that a lot of children won't be going to school today." 
 
 David Quan, walking his dog near Pershing, said his son would be in class at Lamar High School. 
 
 Although concerned about the threat, Quan said it wasn't as disconcerting as a more specific one the high school received last year. 
 
 "We listened carefully to the information from HISD," Quan said of the automated phone call Wednesday evening. "It sounds like such an unspecific threat, so similar to threats in other cities that also weren't specific (and proved not to be legitimate)." 
 
 Alison, who declined to give her last name as she dropped off her son at Pershing, said such incidents put the school district in a bad situation. 
 
 "If they don't do anything, they're criticized, and if they announce it, they're criticized," Alison said. "It's finals week. If the kids miss, their grades will be affected." 
 
 Edgardo Hernandez, who has one son at Pershing, said he wasn't afraid of the threat. "God is with us," he said. 
 
 (Listen to HISD's message below. The story continues after the audio file.) 
 
 The email was received by HISD at 8:17 p.m. Wednesday, according to chief of staff Jason Spencer. 
 
 District officials confirmed that Dallas ISD and Miami-Dade public schools received nearly identical messages to the one sent to HISD. And these emails, officials said, were very similar to those sent a day earlier to the larger Los Angeles and New York districts. 
 
 HISD leaders did not disclose specifics of the email, citing an ongoing law enforcement investigation. 
 
 “The safety of our students and staff has always been my No. 1 priority,” Superintendent Terry Grier said in a brief interview Wednesday night after consulting with police and deciding not to cancel school. “Even though the threats in L.A. and New York turned out to be hoaxes, we’ve taken it seriously.” 
 
 HISD is the nation’s seventh-largest school district, enrolling roughly 215,000 students in about 280 campuses. 
 
 Dallas Independent School District staff members said they received a similar threat about 8 p.m. Tuesday at Pinkston High School and Martinez Elementary School. 
 
 Officials said Dallas ISD have remained in contact with the Dallas Police Department as well as the Joint Terrorism Task Force since being made aware of the threat. A sweep of both Pinkston High School and Martinez Elementary was conducted. Bomb sniffing canines were brought to each campus. 
 
 At 2:20 a.m. Thursday, police found no credible threat and released the buildings back to the district. Our schools have been deemed safe and the district will be open for normal business today. Beefed up police presence is expected at district campuses. 
 
 The New York and Los Angeles school systems, which both received email threats Tuesday, took different approaches, with L.A. shutting down more than 900 schools and New York dismissing it as a hoax. Those messages, however, were distinct. 
 
 The email sent to school officials in New York said 139 attackers would launch an assault with guns and bombs and all would die in the name of Allah. The Los Angeles email, however, mentioned 33 attackers, according to U.S. Rep. Brad Sherman, a former chairman of the House Subcommittee on Terrorism. 
 
 RELATED: School threats prompt proposals for tougher penalties 
 
 While it’s unlikely that a few dozen people could plan a coordinated single-day assault on the nation’s second-largest district without drawing the attention of law enforcement, the idea that 139 people could do it in New York is downright “fanciful,” the California Democrat said. 
 
 “That is the biggest difference between these emails,” Sherman told the Associated Press. 
 
 “Thirty-three was not terribly credible, but 139 is outlandish.” 
 
 FBI officials in Houston said late Wednesday that they were unaware of any threats to HISD campuses. An FBI spokeswoman said she would check Thursday with the agency’s Joint Terrorism Task Force but had no further information. 
 
 The email threat came just two days before HISD will be closed for winter break. 
 
 “You have to think of absolutely every precaution with this type of event,” said Zeph Capo, president of the Houston Federation of Teachers union. “I understand HISD is doing that.” 
 
 “That whoever’s behind this would target schoolchildren is very upsetting,” Capo added. 
 
 “Teachers more and more each and every day are in the line of fire protecting kids, quite literally. It’s a new reality we’re waking up to in today’s day and age. It’s extremely unfortunate.” 
 
 Houston ISD school board president Rhonda Skillern-Jones said the district has received threats in the past but not identical to this one, which follows the terrorist-linked mass shooting in San Bernardino, Calif. She said the district will have increased security at schools Thursday and other law enforcement agencies were alerted. 
 
 “The FBI and our surrounding agencies are professionals at this,” Skillern-Jones said. “They are the best source of intelligence for these things. If they don’t believe it’s a credible threat, I don’t imagine we would cancel school." 
 
 Chronicle reporters Mike Glenn and Emma Hinchliffe contributed to this report, which contains material from the Associated Press.
– Some 640,000 kids in the nation's second-largest school district won't be getting a second terror-related day off from school. Officials in the Los Angeles Unified School District say all 900 schools have been inspected following an emailed threat that has now been discredited by the FBI and they plan to reopen for classes Wednesday morning, reports the Los Angeles Times. A similar threat, supposedly from Islamic radicals, was received by officials in New York City, who rejected it as a hoax almost immediately. Gawker reports that both emails, which threatened attacks involving bombs, guns, and nerve gas, came from a profanely named server associated with the message board "8chan." Officials trying to trace the emails say they were routed through Germany but probably didn't originate there, the Times reports. School board officials, LA Mayor Eric Garcetti, and LAPD Chief Charlie Beck defend the decision to close down schools, saying the threat was specific enough to be taken seriously, KTLA reports. "When parents make their determination about the decisions that were made today," Beck says, "I would ask them to look at it this way: If you knew what the superintendent and the school board knew at 5:30 this morning, when the decision had to be made, would you have sent your child to school? Every parent I've asked said, no, of course not."