Every year 10 million people funnel in and out of America's jails and prisons. And every year some of them get lost. Recently there have been two high-profile cases of such inmates — one who got out years too early, and one who stayed years too long. Both had disastrous consequences.
In January, Evan Ebel walked out of a Colorado prison four years too early. Two months later, he allegedly rang the doorbell of Tom Clements, the head of the Colorado Department of Corrections, shot him in the chest and killed him. Ebel was shot and killed by police two days later.
Colorado officials say Ebel's early release was a clerical error.
Then there's the case of Stephen Slevin, a man who was pulled over for driving under the influence in New Mexico. Jail administrators left him in solitary confinement for almost two years and seem to have forgotten about him. He was never brought before a judge and never saw a lawyer. At one point he pulled out his own tooth. The county there just agreed to pay him $15 million.
"I'd be very surprised if there is a county jail anywhere in America that hasn't released a pretrial prisoner early or held one longer," says Art Wallenstein, who heads the Montgomery County Department of Correction and Rehabilitation in Maryland. He's been running jails for more than 30 years.
Wallenstein says it seems like a simple task: Release inmates on their release dates. But consider his stats: He has 2,000 inmates at any given time, and 10,000 inmates go in and out of his system every year. Getting the dates right can be tricky.
"You could have simply a wrong number placed on a release document," Wallenstein says. "You could have an X drawn through a case by mistake. You could have a detainer that just came in as someone was being released. I've been doing this for a terribly long time, and it hasn't got any easier."
Wallenstein has a team of case managers to review the status of every person in his jail. But not all facilities can afford that.
There are few national statistics about how many inmates stay too long or get out early. Some may not know when they're supposed to get out, and few who get out early would likely speak up.
But advocates say the problem is just as prevalent in prisons as it is in jails.
"For the most part, sentence calculations are being done by hand," says Michela Bowman, senior program associate at the National Council on Crime and Delinquency.
Bowman says the criminal justice system depends on court clerks to record judges' orders correctly, prison and jail administrators to properly read those instructions, and facility staff to accurately add and subtract good-time credits.
Throw in complicated sentencing guidelines, and Bowman says it's easy for mistakes to slip by, especially with inmates who may not be advocating for themselves.
"Without question, they are folks who are not represented by a private attorney," she says. "These are poor people for the most part, and they are people who don't necessarily have somebody on the outside who's advocating for them."
Bowman and other experts say the inmates most vulnerable to overstays are the mentally ill — about half the inmates currently incarcerated, according to a government study.
"They don't understand the system, they don't know what to ask for, their families don't know who to call," says Melissa Neal, a senior research associate at the Justice Policy Institute.
"We have case workers, mental health specialists who don't have time to do all of these reviews," she adds.
Neal says the mentally ill often spend long periods in jail without charges because state hospitals are often full.
"There was someone, when I worked in Tennessee, who had been in jail for two years and had not had a court hearing yet, just because they had not had room at the state hospital to treat that person," Neal says.
Asked if that's legal, she says, "Technically, no, but the judge was making that order."
Neal and other experts say if someone is locked up for too long, the cost is borne by taxpayers. If someone is not locked up long enough, the public is still left picking up the pieces.