California investigators are offering a reward of $100,000 for information related to the cold case killing of Thea Slater, who was attacked and killed while working over 20 years ago, police records show.

Slater was 39 when she was repeatedly stabbed to death while alone at work on Oct. 19, 2002, in San Francisco, police said. She was working on the third floor of a townhouse when her killer slipped in through an unlocked entrance, local affiliate KTVU reported Tuesday.

The person or people are believed to have initiated the attack on the top floor, with the struggle continuing onto the bottom floor, the outlet reported.

MAN, 75, ARRESTED IN CALIFORNIA OVER 2005 COLD CASE KILLING OF 56-YEAR-OLD WOMAN

Slater, a single mom, could not be saved. But police have not had any leads related to the killing since 2002, officials said. 

More than 20 years later, the San Francisco Police Department has erected new signs related to the cold case, offering the $100,000 reward for information leading investigators to the killer, KTVU reported. 

WEST VIRGINIA MAN ARRESTED IN 1985 COLD CASE, SAID HE STABBED 13-YEAR-OLD BOY IN ARGUMENT OVER BIKE: POLICE

Police will also reportedly be conducting new tests on DNA recovered from the crime scene.

Her daughter, Tiyesha Slater, told KTVU her mother "did not deserve this." 

"Justice will be served," Tiyesha Slater reportedly said. "I love you mommy. I miss you."

CLICK HERE TO GET THE FOX NEWS APP 

Homicide detectives are asking anyone with information related to the case to contact SFPD’s Department Operations Center at 415 553-1071