By Pam Zekman

CHICAGO (CBS) — Chicago police are now calling for DNA testing and witnesses to come forward after more than 50 Chicago women were strangled and killed.

CBS 2 Investigator Pam Zekman first raised the red flag about a potential serial killer on the loose.

Her explosive report has victims’ families and community members demanding answers.

Friday the head of the Chicago Police Department finally told CBS 2 exactly what’s being done to solve these murders.

“This isn’t something we’re going to sweet under the rug or put up on the shelf for it to disappear,” said CPD Supt. Eddie Johnson. “We still investigate these cases.”

Johnson says he’s deeply concerned about these 50 deaths.

“There’s simply nothing there right now that suggests that we have serial killers in the City of Chicago,” Johnson said.

But the head of the Murder Accountability Project, Thomas Hargrove, says research might show otherwise.

“It’s highly unlikely these 50 women were murdered by 50 separate men,” Hargrove said.

He says his computer formula highlights a pattern of killings — 50 females strangled and dumped since 2001 that could signal a serial killer.

“Overall those are the three killing fields: South Side, Far South Side and Chicago’s West Side,” Hargrove said.

“Horrific cases, you know, tragic and nobody deserves to die in that fashion,” Johnson said.

Gwendolyn Williams is one of the victims. Her sister, Sharon Pritchett, remembers the day she was killed.

“She was fighting for her life,” Pritchett said. “That’s the first thing we though. She was not going to go down without a fight.”

Johnson says investigators can take another look at DNA evidence.

“We’re looking at them now to see if we can go back and do some additional testing to see if that will help us find out who these individuals are,” Johnson said.