The notorious convicted murderer has had a difficult time in prison in the 25 years since she drowned her two sons

On October 25, 1994, Susan Smith told police that she had been carjacked by a black 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.

Get push notifications with news, features and more.

As her story began to unravel, Smith admitted that there was no carjacker, and that she had let her car roll into a lake with Michael, 3, and Alex, 14 months, still strapped in their car seats.

Her 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.

Image zoom

Now, 25 years later, Smith, now 48, has spent more than half of her life in prison — and records obtained by PEOPLE show that her incarceration has been marred with disciplinary infractions for self-mutilation and drug use.

Last March, she was promoted to be a Wardkeeper Assistant, in which she is responsible for the daily operation of her housing unit. In 2017, she was working in the prison as a landscape laborer — a step down from a position she previously had, as a senior groundskeeper.

At least six times in the past two years, Smith has had severe enough medical issues that she has been transferred to another facility for outpatient treatment. The nature of her treatment has not been made public.

In the past nine years, Smith 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.

Image zoom Susan Smith in August, 2017 South Carolina Department of Corrections

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 South Carolina newspaper. “Mr. Cahill, I am not the monster society thinks I am,” she wrote to reporter Harrison Cahill. “I am far from it.”

Image zoom Michael (left) and Alex Smith Dave Martin/AP

“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.”