Call them the lost boys, assigned to oblivion by a neglectful state. At least 50 graves have been found on the grounds of the Arthur G. Dozier School for Boys in Marianna. It was a reform school that opened in 1900 and closed last year after an investigation found widespread abuse at the facility over decades. State officials say the school was shut down for “budgetary” reasons, but the shame of what went on there unchecked for so long likely prompted the closure.

Closing the school doesn’t end this ignominious chapter in Florida’s history. Democratic Sen. Bill Nelson rightly is asking the U.S. Justice Department to conduct a full-scale investigation. For those lost boys and their families, that is exactly what needs to be done.

Roger Dean Kiser, a former inmate, wrote of his abuse there in The White House — An American Tragedy. He called the place “a concentration camp” where he and other boys were tortured and abused physically and sexually in the 1950s and ’60s. The White House, an 11-room building on the school grounds, is where most abuse took place, Mr. Kiser writes.

Other former inmates — you really can’t call them students — recall beatings with metal-lined leather straps and being taken to the “rape room.” The boys were farmed out for labor by prison administrators, who profited from the forced work. Evidence shows that runaways were shot to death or killed by blunt trauma.

In 2008, after several former inmates spoke up about their unspeakable treatment, then-Gov. Charlie Crist ordered the Florida Department of Law Enforcement to investigate. The FDLE found that 81 inmates had died at the school over the years and that 31 were buried on school grounds.

No one was called to task by FDLE’s findings. Not one single person. University of South Florida anthropologists and archaeologists have continued the search, using ground-penetrating radar for further exhumations. The largest grave site is next to a dump. It was long called the “colored” section. The graves are marked with PVC pipe, but the markers don’t correspond to actual interments.

The USF team found that between 1911 and 1973 at least 98 boys between the ages of 6 and 18 and two adults died at the facility. The team last week reported locating 19 more graves. More may yet be uncovered. The USF experts will return to the excavation site in what is believed to be the white inmates’ burial ground and must finish their work by January.

Some, like Mr. Kiser, were only there because they were orphans — abandoned by their families and then warehoused by a state government oblivious to what was happening at the so-called “reform” school. Others were sent there for punishment — and what punishment it must have been.

A relative of one victim, Glen R. Varnadoe, wrote to Sen. Nelson seeking information about the whereabouts of the remains of his uncle, Thomas, who died at the school in 1935 after being incarcerated there for just 35 days. Mr. Varnadoe wants to bury his uncle’s remains in the family plot in Brooksville. Sen. Nelson wrote to Attorney General Eric Holder, requesting the federal investigation. The Justice Department must comply. As Mr. Nelson said, “For the sake of those who died and their surviving families, we’ve got to find out what happened.”

Yes, uncover the whole ugly truth and go after those still alive who let this abuse go on for nearly 75 years. Someone must be called to account for the horrors at Dozier.

The state, after all, was the ultimate authority over the facility.

We can’t bring back those boys, but we can give them final recognition and dignity in death.