Chilling new vision has emerged of what police claim to be former reality TV star Tamika Chesser shortly before she allegedly set fire to her partner’s remains.

Her sister has spoken out for the first time, telling 9News the allegations are not in line with her character.

Police claim the footage of a woman on a morning walk with her dog’s leash in one hand and what looks like a jerrycan in the other is Chesser.

About three hours later police say they uncovered her alleged sinister crimes.

Watching from Queensland, her distraught family were shocked to learn of the allegations against Chesser.

The former Beauty and the Geek contestant allegedly set fire to partner Julian Story’s remains inside their Port Lincoln, South Australia, unit two days after she allegedly killed him and dismembered his body.

Her sister said in the months before she had concerns for Chesser’s mental health.

“It’s my sister but that’s not who she is or the Tamika we know. That’s not the Tamika anyone knows,” she said.

“It just started getting worse you know and she started being in and out of mental health.

“She seemed, like I don’t know, I guess OK. She didn’t mention anything and she just told everyone she loves them.”

Chesser remains in police custody at a mental health facility in Adelaide.

Her family is restricted from talking with her.

“She’s still unresponsive at the moment,” her sister said.

Police still haven’t been able to formally interview the 34-year-old as they continue their search for Julian’s missing remains in Port Lincoln.

Story’s body was found without his head after police responded to a small fire in the yard of the house about 3.35pm on June 19.

Chesser, 34, has been charged with murder.

Today police divers sifted through the shallows along the foreshore in a grim search for Julian’s head.

Despite extensive searches, Story’s remains still haven’t been found but the search won’t stop with investigators determined to bring closure to his family.