ALSIP, Illinois (CNN) -- Four people face felony charges after authorities discovered that hundreds of graves were dug up and allegedly resold at a historic African-American cemetery near Chicago, Illinois, authorities said Thursday.



Dozens of graves at Burr Oak Cemetery were desecrated by workers as part of a financial scheme, authorities say.



Cook County Sheriff Tom Dart said the four would resell the plots in Burr Oak Cemetery in Alsip, excavate the graves, dump the remains and pocket the cash.



"This was not done in a very, very delicate way, folks," he told reporters at a news conference Thursday.



"They would excavate a grave and would proceed to dump the remains wherever they found a place to do it in the back of the cemetery. This was not moving graves; this was not replacing graves; this was dumping of them."



In some cases, graves were stacked on top of each other, they "literally pounded the other one down," Dart said. In all about 300 graves may have been dug up in the cemetery, he said.



Authorities identified those charged as Carolyn Towns, an office manager for the cemetery; and Keith Nicks, Terrance Nicks and Maurice Daley, all gravediggers.



Each has been charged with dismembering a human body, a felony charge for which sentences range from 6 to 30 years, Anita Alvarez, Cook County state's attorney, said at the news conference.



Steven Watkins, an attorney for Towns, said his client is innocent. "Somebody is apparently making false accusations against my client," he said. "She's maintaining her innocence."



The Cook County state attorney's office said the other three charged were being represented by the public defender's office, and a message left at that office was not immediately returned.



Bail was set at $250,000 for Towns and $200,000 for the other three, Alvarez said. None had posted bail by late afternoon Thursday, the sheriff's department said.  Watch officials announce the charges »



It was not immediately known if the four had legal counsel.



Authorities began investigating the cemetery -- where, among others, lynching victim Emmett Till, blues legend Dinah Washington and some Negro League baseball players are buried -- about six weeks ago after receiving a call from its owners who had concerns about possible "financial irregularities" regarding the business, Dart told CNN earlier this week.



"This crime, it's a whole new dimension," Alvarez said. Authorities also suspect that Towns pretended to set up a memorial fund for Till and pocketed the funds, Dart said.  Watch sheriff discuss gruesome revelation »



He told CNN that groundskeepers, who have not been implicated in the scheme, have said that the grave of Till -- whose 1955 lynching at age 14 helped spark the civil rights movement -- has not been disturbed.



The Rev. Jesse Jackson, who was also at the news conference, noted the high-profile names of some of those buried in the cemetery, but said, "everybody here is special, and every family has special needs and special hurt, special grief."



Most of the excavations occurred in back lots, where the plots were older and not frequently visited, Dart said earlier this week. However, other plots may have been disturbed, as well.



The cemetery's current owners, who could not be reached by CNN for comment, have operated it for more than five years but are not believed to be involved in the alleged scam, Dart said.



He said the workers may have doctored records to cover their tracks and noted that the cemetery holds all the records of who is buried and where.



"There's virtually no regulations whatsoever (for cemeteries)," Dart said. "Most all of the documents and everything are housed here."



Investigators are trying to determine the scope of the alleged scheme and plan to use thermal-imaging devices to further examine other graves to see if they have been tampered with, Dart said.



The FBI, forensic scientists and local funeral directors have been called in to help in
Who was charged What did Jackson say how many graves may have been dug up? What number of people charged? Who is buried there
Keith Nicks, Terrance Nicks and Maurice Daley, "everybody here is special, and every family has special needs and special hurt, special grief." about 300 Four lynching victim Emmett Till, blues legend Dinah Washington
question: Who was charged, answer: Keith Nicks, Terrance Nicks and Maurice Daley, | question: What did Jackson say, answer: "everybody here is special, and every family has special needs and special hurt, special grief." | question: how many graves may have been dug up?, answer: about 300 | question: What number of people charged?, answer: Four | question: Who is buried there, answer: lynching victim Emmett Till, blues legend Dinah Washington