Susan Smith Female Child Killer

Susan Smith has spent more than half her life in prison for the 1994 murder of her two young sons — and records obtained by PEOPLE show that her incarceration has been marred with disciplinary infractions for self-mutilation and drug use.

Smith, who turns 46 on Tuesday, became South Carolina’s most infamous inmate more than two decades ago. In October 1994, she told police that she had been carjacked by a man who had taken off with her two young sons still in her car. For 9 days, she made tearful pleas for their safe return.

But it was all a lie.

As her story began to unravel, Smith admitted that there was no carjacker. (Smith had blamed the crime on a nonexistent black man, which led to outrage among the black community.)

Smith finally told police that she had let her car roll into a lake with Michael, 3, and Alex, 14 months, still strapped in their car seats. Her alleged motive: She was secretly dating a man who didn’t want children. The story became international news, even landing on the cover of PEOPLE. Smith was convicted of two counts of murder and is serving a life sentence in Leath Correctional Institution in Greenwood, S.C.

PEOPLE has pulled her jailhouse records and found that her incarceration hasn’t been easy. This summer, she began working in the prison as a landscape laborer — a step down from a position she previously had, as a senior groundskeeper.

In the past seven years, she has been disciplined at least five times for various infractions, including self-mutilation and the use and possession of narcotics or marijuana. Each infraction has resulted in the loss of privileges, including loss of visitation, canteen and telephone privileges.

Twice in 2010 and once in 2015, she was disciplined on drug charges, losing privileges for more than a year.

In 2000, Smith, then 28, was disciplined for having sex four times with 50-year-old prison guard Houston Cagle. (He pleaded guilty and spent 3 months in jail.)

The following year, a prison captain, Alfred Rowe, also pleaded guilty to having sex with Smith and was sentenced to five years probation.

But Smith claims she has been misunderstood.

In 2015, Smith wrote a letter defending herself to The State, a local newspaper.  “Mr. Cahill, I am not the monster society thinks I am,” she wrote to reporter Harrison Cahill. “I am far from it.”

“Something went very wrong that night. I was not myself,” she wrote. “I was a good mother and I loved my boys. There was no motive as it was not even a planned event. I was not in my right mind.”

But Smith’s ex-husband — and the father of the boys — told PEOPLE in 2010 that he has never fully recovered from the pain. “There’s always this nagging and gnawing heartache,” David Smith said, “It’s there every day, even if I’m not always conscious of it.”

According to the jail, Smith is not permitted to give interviews. A call to her former attorney has not been returned.