Massachusetts has paid out $8.34 million to people wrongfully convicted of felonies under a 2004 law that allows up to $500,000 in compensation for people imprisoned on false charges.

The law was passed as the increased prevalence of DNA testing brought wrongful conviction cases into the public spotlight. At the time, the Boston Globe reported that New York, Texas, California, and Maryland had similar statutes; now, 29 other states and Washington, D.C. have passed compensation laws.

Under the Massachusetts statute, wrongfully convicted prisoners must prove their innocence to receive compensation. They must first prove to a court that they are eligible for compensation, meaning that they were either granted a full pardon or had their cases overturned in a manner that "tends to establish the innocence of the individual." Prisoners freed solely due to prosecutorial misconduct or on technicalities are not eligible under the law.

With that hurdle cleared, former inmates then must prove a series of claims: that they never pleaded guilty to the offense, that they were sentenced to at least a year in prison, and, crucially that they did not commit the crime. The process is a higher burden than winning a not-guilty verdict in the criminal justice system, where the burden is on prosecutors to prove the guilt of the accused.

Compensation cases are also not subject to rules of evidence typical of criminal trials. Evidence cannot be excluded, even if it was obtained in violation of the Fourth, Fifth and Sixth Amendments to the Constitution, according to the compensation law.

Cases can take a long time to resolve, with two years allowed for evidence discovery under the trial schedule used for compensation cases.

63 people have filed for compensation under the law, which also applied to people convicted before its enactment, according to a listing of cases and judgments obtained by MassLive in a public records request.

David Siegel, a professor at New England Law, was critical of the statute's effectiveness in an interview with MassLive.

"I think the capped payment level is unfair because it's not reflective of the length of a person's compensation," Siegel said. "And it's inefficient since it encourages delay because there's a maximum level people can recover."

Some states, like Tennessee, have higher payout caps; others, like Texas, pay a set amount per year of wrongful imprisonment. Massachusetts' fixed $500,000 cap leads to cases where people wrongfully imprisoned for decades end up with less money than if they had spent that time working for the state's average wage, Siegel said.

"I think people who are wrongfully convicted deserve compensation for the wrongful deprivation of their liberty," Siegel said. "I think they deserve more than just payment for not having been able to work, and this doesn't even do that."

Of the claims brought under the law, 19 were dismissed, 23 were settled, for sums ranging from $60,000 to the legal maximum, and 17 are still pending.

Massachusetts' compensation law is not the only recourse for wrongfully convicted prisoners, who can also file lawsuits.

But the state's settlements with claimants typically include a clause that the state can reclaim the money if the petitioner later wins damages from a federal civil rights suit, the Attorney General's Office told MassLive. In two cases the state gave out a total of $1 million that was later returned due to those settlement terms, in addition to the other $8.34 million awarded.

Just three cases have gone to trial, with two of those decided in favor of the Commonwealth. Ulysses Charles, who served 17 years before DNA evidence cleared him of rape and robbery charges in 2001, is the only former prisoner to win a judgment against the state at trial, and was awarded $500,000.

One case was dropped after the former prisoner amended his complaint and did not request compensation under the 2004 compensation law.

Check out the full list of cases below: