Antoine Payne

Antoine Payne, a former inmate, runs a ministry targeted at other people who have been released from prison. (Lloyd Fox / Baltimore Sun / March 21, 2014)

After Gregg Thomas pleaded guilty in 2004 to killing a teenager, a Baltimore judge ordered him to serve 15 years in prison. He was out in less than 10, and by last week he had been charged in the shooting ambush of off-duty Baltimore Police Sgt. Keith Mcneill.

The shooting, which left Mcneill in critical condition, put the spotlight on a poorly understood feature of corrections policy that reduces most Maryland sentences. Thomas was able to leave prison early because he had received credit for good behavior and had completed work and education programs that helped him shave off more than a third of his sentence.

Such programs are commonplace across the country, and corrections officials describe them as essential enticements that help maintain discipline and prepare thousands of inmates to re-enter society. But the system can frustrate victims' families, who can be surprised by a prisoner's early release. And for proponents of tougher sentencing laws, the shooting of Mcneill is the most recent example of an early release gone wrong.

State Sen. James Brochin, a Baltimore County Democrat who has sponsored legislation to toughen sentences for gun offenders, called the system of allowing credits for violent criminals "a total waste of time."

"I think it's very rare that you rehabilitate a murderer," he said.

But Antoine Payne, a former inmate who runs an East Baltimore Christian group for ex-prisoners, said the credits are the justice system's way of accounting for the good decisions convicts make after their sentences are handed down.

"There does come a time when a person has accomplished much and grown, and early release makes sense," said Payne, who runs the Philemon Ministry. "The reality is, even the judge doesn't have everything before him to make the absolute decision."

Cheri Nolan, president of Justice Solutions of America, which advocates for inmates, said states have been expanding the use of credits to reduce prison populations.

"The force behind it has really been budgetary," said Nolan, a former official at the Justice Department. "It's forced governors to take a second look at sentencing policies."

Even the federal prison system, a bastion of lengthy and mostly unassailable sentences, might be in for change. A bill making its way through the Senate with bipartisan support would expand early release in federal prisons.

Maryland's rules are based on a complex system of credits that has led inmates and corrections officials in some cases to come to vastly different conclusions about release dates. The state can reduce sentences based on factors that include the type of offense, the completion of high school courses and vocational training.

State corrections officials said the credits toward early freedom are an important way of driving down recidivism.

"Making inmates successful taxpaying citizens who are in much better shape when they come out of prison than when they entered is the goal," said Mark Vernarelli, a spokesman for the state corrections department. "Inmates who take advantage of the credits system often stand to benefit tremendously from their education and job training."

Thomas had participated in those programs, and a public defender said at a court hearing that her client had found work, but police say his efforts at self-improvement behind bars didn't keep him out of trouble.

Mcneill, a 19-year-veteran assigned to Baltimore's Eastern District, was critically wounded when Thomas was attacked him March 14 outside a Belair Road auto shop, police say. The incident came just over a year after Thomas' release from what was technically a 30-year sentence.

Thomas was arrested in 2003, a little more than a week after 17-year-old Davon Lindsey was shot and killed in the 900 block of N. Chester St. in the Middle East neighborhood. Police received a tip and raided his aunt's home there, where Thomas was living, and found the murder weapon.

Thomas' aunt told investigators that he and Lindsey had been involved in a dispute over drug turf, according to court records. Thomas initially said he killed Lindsey in self-defense but eventually agreed to plead guilty to second-degree murder.

Circuit Judge John M. Glynn handed down the maximum 30-year sentence but immediately suspended half of it. Though the suspended portion of the sentence would hang over Thomas' head when he got out, he would not have to serve it if he stayed out of trouble.

At the hearing, Glynn explained that Thomas probably would serve even less than 15 years. That's because Thomas was allotted credits for good behavior as soon as he stepped into prison.

Prisoners serving sentences for violent crimes get five days a month removed from their sentences for good conduct; the same rate applies to some drug-dealing offenses. Everyone else is given 10 free days per month. Those convicted of serious sexual offenses against children under age 16 cannot receive credits.