Susan Smith may’ve given a tearful plea before being denied parole this week, but many are left unconvinced she’s completely changed her ways … including yet another one of her former prison guards who knew her well behind bars.

Felicia Mungo, a former guard at Camille Graham Correctional Center in South Carolina, tells TMZ … she isn’t sold on Susan’s tears, explaining to us that she felt the weeping during the hearing was a bit “disingenuous.”

For those unfamiliar, Susan was arrested in 1994 after strapping her sons — Michael, who was 3 years old,  and Alex, who was 14 months old — into their car seats before pushing their vehicle into a nearby lake. She was convicted in 1995 and sentenced to life with the possibility of parole … which she was first eligible for this week.

Still, Felicia doesn’t think Susan is truly sorry for her wrongdoings and hasn’t grasped the full magnitude of the situation … citing her lack of remorse for past racist behavior as an example.

Susan infamously claimed her vehicle had been carjacked by a Black man in the early days of the investigation … an accusation which Felicia says put Black men in the area in serious danger.

TMZ also spoke to Alfred Rowe this week — the disgraced former prison guard who was fired for having a sexual relationship with Smith in 2001, and later convicted of the crime — who shares Felicia’s assessment of Smith … saying Smith’s emotion in front of the parole board was a total fabrication. Smith was moved from the Camille Graham prison as a result of the misconduct, to her current location, Leath Correctional Institution in South Carolina.

Of course, there’s Susan’s ex-husband David to think about … who was very vocal and spoke out against her possible parole at Wednesday’s hearing.

Felicia believes Susan will eventually get out … but thinks the killer mom needs to truly be sorry for everything before getting released.