"Grim Sleeper" Update: Pictures Released by LAPD Spark Four Missing Persons Cases

LOS ANGELES (CBS/AP) The Los Angeles Police Department has opened four new missing person cases stemming from the release of more than 100 photos taken from the home of suspected "Grim Sleeper" serial killer Lonnie Franklin Jr.

PICTURES: "Grim Sleeper" Serial Killer Suspect's Private Photos

Los Angeles Police Chief Charlie Beck told KTLA-TV Thursday that the cases were opened after investigators received hundreds of calls with information regarding the roughly 180 photos of unidentified women that were found in the suspect's South Los Angeles home.

Beck says investigators have been able to identify more than 50 of the women in the photos so far. At least 79 of the photos have been taken down from the LAPD's website after friends, relatives or women pictured in the photos contacted authorities to confirm their identities, reports The Los Angeles Times.

LAPD officials would not divulge any specifics regarding the four missing person cases. They did say that they are believed to date back to the early 1990s, reports the Times.

Investigators spent years trying to crack the "Grim Sleeper" case. Franklin's arrest finally came in July after his son was swabbed for DNA after being arrested on an unrelated matter, which authorities say ultimately linked the 57-year-old to evidence from the killings.

Beck says it was a tough decision to release the photos because many included women in sexual acts.

Franklin is accused of killing 10 women in the Los Angeles area from 1985 to 1988 and from 2002 to 2007. The 14-year pause led to the nickname "Grim Sleeper." He has pleaded not guilty to charges of sexual assault and murder.

COMPLETE COVERAGE OF "GRIM SLEEPER" CASE ON CRIMESIDER