BALTIMORE (AP) — The U.S. Coast Guard says it's looking for a man who has cost the service about $500,000 after responding to nearly 30 of his fake distress calls. 
 
 In a press release published Friday, the Coast Guard says the 28 calls have originated from around the area of Annapolis, Maryland. 
 
 Each call involved the same male voice and used an emergency radio channel. He's been making the calls since July 2014. The two most recent calls were made on the night of July 21 and the early morning of July 22. 
 
 The Coast Guard also says hoax calls distract rescuers from real emergencies, putting both the public and the responding crews at risk. ||||| A hoax caller in Maryland cost the Coast Guard about $500,000 in the past two years by making false distress alerts. 
 
 The caller made 28 false distress alerts from Annapolis, Maryland, beginning in July 2014, according to the Coast Guard. The two most recent calls were received Thursday and Friday, the Coast Guard reported. They also said they determined the calls to have originated from Annapolis, between Loretta Heights and Admiral Drive. 
 
 The estimated cost of the responses to these false alarms is $500,000. 
 
 The Coast Guard provided an audio file of the caller, in which the caller repeats “mayday” -- a word used to indicate distress at sea. 
 
 Making false distress calls is a felony, punishable by a maximum of six years in prison, a $10,000 civil fine, $250,000 criminal fine and a reimbursement to the Coast Guard for their efforts, the Coast Guard said. 
 
 The Coast Guard also said such false distress alerts detract from their ability to respond to actual alerts. 
 
 “A hoax call is a deadly and serious offense,” said Lt. Cmdr. Sara Wallace, who heads the response sector in Maryland. “Calls like these not only put our crews at risk, but they put the lives of the public at risk.” 
 
 Anyone with information about the caller is asked to contact the Coast Guard's regional command center at 410-576-2525 or email investigators at CGIS-Baltimore@uscg.mil. ||||| 19 Gallery: Rescue crews respond to report of boat explosion 
 
 SANDY HOOK — The U.S. Coast Guard, State Police and other agencies in New Jersey and New York responded to a report that a large boat exploded off the coast of Sandy Hook early this evening. 
 
 However, three hours after those reports had surfaced and emergency crews mobilized a massive search and rescue operation, the Coast Guard was unable to find any evidence of a damaged boat or any victims. The search was officially suspended late tonight, and the Coast Guard said it is investigating whether the initial distress call was a hoax. 
 
 As of 7:30 p.m., dozens of EMS crews, ambulances and helicopters at Gateway National Recreation Area had left the scene without treating any passengers. 
 
 "Basically there are no patients coming," said John Grembowiecz, the New Jersey EMS Task Force leader from the scene. "It has not been verified, so we are demobilizing now." 
 
 The six medevac helicopters, 15 ambulances and two medical buses with the capacity to carry 20 patients were all released from Sandy Hook, he said. 
 
 The initial report of an explosion came in around 4:20 p.m. about 17 miles out to sea, the Coast Guard said. At the time, the agency said 21 people had jumped ship. Some escaped on lifeboats, the Coast Guard said. 
 
 Nine people were reported injured, according to Gateway National Recreation Area spokesman John Warren. The Coast Guard asked the Gateway National Recreation Area help arrange transportation for the injured, Warren said. 
 
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 As of 5:50 p.m., the Coast Guard had not yet found any debris or lifeboats. The agency said the initial emergency call they received said the boat, a yacht named the Blind Date, exploded and sank in the Atlantic Ocean. 
 
 Two Coast Guard helicopters, three 47-foot motor life boats, three New York Police Department helicopters and a Nassau County helicopter responded to the scene. Two good Samaritan boats in the area of the accident were also assisting, a Coast Guard spokesman said. 
 
 The N.J. State Police had two medevac helicopters docked in the area waiting to assist in the rescue effort, according to Sgt. Brian Polite, a spokesman for the agency. 
 
 A large staging was set up on a fenced-off field at the Fort Hancock area of Sandy Hook. Six helicopters and numerous emergency vehicles, including trucks, SUVs and fire trucks were at the staging area, waiting for the victims to arrive. Vehicles were from as far away as North Brunswick. 
 
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 As of around 6:50 p.m. three of the helicopters took off from the staging area, appearing to be headed inland without any of the passengers. 
 
 Of the 10 ambulances on the scene, seven were seen leaving the area. Several ambulance drivers said they had been released. Fire engines were also leaving, creating a caravan of emergency vehicles snaking away from Sandy Hook. 
 
 Max Ross, an emergency medical technician from Rumson said all rescue crews that had gathered at the staging area were released as of around 7:15 p.m. except for crews from Sea Bright and Highlands. 
 
 "At this time (the report of an explosion) is unfounded." Ross said. "They're still treating it as if it's real, but they haven't found anything." 
 
 This case is now being investigated as a possible hoax call, the Coast Guard announced late tonight. The agency said it offers a reward of up to $1,000 "for information leading to the arrest and prosecution of anyone responsible for making a false distress or hoax call to the U.S. Coast Guard." 
 
 Making a false distress call is a federal felony with a maximum penalty of five to 10 years in prison, the Coast Guard added, along with a $250,000 fine and reimbursement to the Coast Guard for the cost of performing the search. 
 
 Star-Ledger staff writers Brian Donohue, Tom Haydon, Brent Johnson, Len Melisurgo, Bobby Olivier, James Queally and Jeanette Rundquist contributed to this report. 
 
 Related coverage: 
 
 • Boat capsizes in Raritan Bay, killing one, while four are rescued from the water 
 
 • Deadly dive off N.J. coast has officials investigating two other mishaps involving same boat 
 
 • Rescue effort for missing Lacey Township man in boating accident halted
– The US Coast Guard says it's looking for a man who has cost the service about $500,000 after responding to nearly 30 of his fake distress calls, reports the AP. In a press release published Friday, the Coast Guard says the 28 calls have originated from around the area of Annapolis, Maryland. Each call involved the same male voice and used an emergency radio channel. He's been making the calls since July 2014. The two most recent calls were made on the night of July 21 and the early morning of July 22. “A hoax call is a deadly and serious offense,” a Coast Guard rep tells NBC4, which notes that such calls are a felony that carry six years in prison, $10,000 civil fine, $250,000 criminal fine, and reimbursement to the Coast Guard. "Calls like these not only put our crews at risk, but they put the lives of the public at risk.”