On a hot June afternoon in 2011, 69-year-old Eunice Hopkins rolled down the windows of her silver BMW, waiting for the air conditioning to kick in before she left a supermarket parking lot.

A tall, disheveled man in a straw hat walked up to her car window, grabbed her arm and demanded the keys, she told police in this Orlando suburb. She screamed and pulled out of the parking space. The man ran into a shopping mall across the street, where officers arrested him.

Mark Jones, a 37-year-old former West Point cadet, suffered from post-traumatic stress disorder and alcoholism, according to court records. He had been arrested before for low-level crimes and served a year in prison after stealing a $400 tool set from a Home Depot.

For the unsuccessful carjacking, however, he was sentenced to life without parole. That means he will never get out of prison, no matter how sober and industrious he has become in his 10 years behind bars.

The number of people serving life-without-parole sentences has soared across the country in the last two decades, rising to 56,000, according to The Sentencing Project, an advocacy group. Some people received these penalties as an alternative to capital punishment, which has fallen out of favor with many prosecutors and the public. The number of death sentences dwindled to 18 last year, and only 2,500 people are now on death row, down from almost 3,600 two decades ago.

But there’s another reason for the increase: A handful of states have embraced life-without-parole sentences to punish “repeat offenders” — even if their crimes didn’t cause physical injury, an investigation by The Marshall Project and The Tampa Bay Times found.

Washington passed the first “three strikes” law in 1993, allowing prosecutors to give life sentences to people convicted even of nonviolent felonies if they met the criteria for “persistent offenders.” At least two dozen states followed suit, including Florida in 1995.

In many states, people sentenced to life used to become eligible for parole after 15 years. But Florida and others virtually ended parole a generation ago, so that life sentences became permanent.

Today, Florida has more than 13,600 people serving life without parole, far more than any other state and almost a quarter of the total nationwide. Though this sentence is widely seen as an alternative to the death penalty, which is used in murder cases, 44% of the people serving it in Florida were not convicted of that crime, according to our analysis of state data.

Part of the reason Florida’s numbers are so high is that it went further than any other state in 1997 by passing an unusual “two strikes” law known as the Prison Releasee Reoffender Act. The law directs prosecutors to seek the maximum sentence for someone who commits a felony within three years of leaving prison, which often means a lifetime behind bars. The law also takes sentencing discretion away from judges.

Read the full article about prison in Florida by Cary Aspinwall and Weihua Li at The Marshall Project.