Forty-two photographs found at the home of suspect Lonnie Franklin Jr. were be posted on Facebook and Twitter on Thursday.
When authorities found the photos, along with hundreds of hours of video, they feared that some of the women could be additional victims.
Some of the images appeared to be innocent snapshots, but most showed women in various states of undress in sexual poses.
View the photos on Facebook or Twitter
58-year-old Franklin is facing ten counts of murder and at least one count of attempted murder.
Investigators say Franklin may be responsible for at least six more murders, but they do not plan to seek criminal charges on the new cases, fearing that might delay the start of a trial.
Detectives linked the additional crimes to Franklin after reviewing hundreds of unsolved homicide cases, missing persons reports, and photos of unidentified women found inside his home.
Franklin was arrested in July of last year and charged with the murders of 10 women in South L.A. over a span of two decades.
Before his arrest, investigators reported that they suspected to eventually find that Franklin was responsible for more than 10 killings.
The bodies of the 10 victims were found outdoors, often in alleys a few miles south of downtown Los Angeles.
The victims were shot, strangled or both, usually after some kind of sexual contact.
Franklin also was charged with one count of attempted "willful, deliberate and premeditated murder" in the case of an 11th alleged victim who survived.
All were known to frequent Franklin's neighborhood before they went missing.
Police say a woman killed in 1988 may have been a victim of Franklin because of similarities between the case and others Franklin is accused in.
After 1988, the killer did not commit any known homicides until 2002. He last struck on Jan. 1, 2007.
The 14-year hiatus between the two distinct sets of killings correspond to a time when Franklin was on disability, a law enforcement source said.
Police have said it's possible the sole male victim, Thomas Steele, who was shot in 1987, was a friend of another victim or discovered the killer's identity.
Franklin has twice been convicted of felonies, according to court records, both for receiving stolen property. One was in 1993 and the other was 2003.
He served a year in jail for the first conviction and was sentenced to 270 days in jail in the 2003 case.
In 1997, he pleaded guilty to one count of misdemeanor battery.
As part of a plea deal, a charge of false imprisonment was dropped, according to court records.
In 1999, he was convicted of misdemeanor assault with a deadly weapon. He was sentenced to 90 days in jail.
he nickname "Grim Sleeper" is intended to convey the fact that a purported serial killer apparently stopped murdering for more than a decade, then became active again in 2002.