Lonnie Franklin Jr. has been charged in 10 Grim Sleeper killings. (Al Seib / Los Angeles Times / July 8, 2010)

Los Angeles police say they have linked two more slayings to alleged serial killer Lonnie Franklin Jr., persuading detectives that he never stopped killing during the supposed dormant period that led to his nickname of the Grim Sleeper.

The Grim Sleeper allegedly killed seven women between 1985 and 1988 and three between 2002 and 2007. Police have been openly skeptical that the slayings stopped during the 13-year gap. On Thursday, they announced the strongest evidence yet that the killings had not ceased: two homicides during the interim involving women slain in the South L.A. area where the other killings occurred.

Franklin, who has pleaded not guilty to murdering 10 people, has not been charged in the new cases.

"I don't think there is a gap," said LAPD Det. Dennis Kilcoyne, who has been leading the Grim Sleeper investigation. "We are continuing to examine many, many old cases now we know Mr. Franklin's identity. We are trying to put together other cases."

Prosecutors accuse Franklin of being one of L.A.'s most prolific serial killers, targeting women on the margins of society - including some prostitutes and drug addicts - over nearly a quarter century. Many of the victims were sexually assaulted just before they were killed and dumped in alleys and trash bins.

After Franklin was charged in July, the LAPD said it was reviewing about 30 unsolved killings to see if any of them could be connected to the Grim Sleeper. Detectives also released scores of still photos found at Franklin's home in hopes that they could yield more clues. Investigators have identified 72 women who contacted authorities after their photographs were released. But 62 of the women remain unidentified.

Kilcoyne said that he expects the search for additional Grim Sleeper victims to continue for several more years and that he would not be surprised if the gap in killings completely closes.

"It's obvious we are far from knowing the true depths of the criminality of Mr. Franklin," LAPD Chief Charlie Beck said. "When this case unravels, people will be even more horrified about what's occurred. We have been putting the pieces of the puzzle together, but the picture is not anywhere near complete. It's just too early to tell."

Franklin's attorney, Louisa B. Pensanti, denounced the LAPD for releasing information about the new cases before prosecutors have decided whether to file charges.

"Once again the Los Angeles Police Department has gone to the 'Court of Public Opinion' instead of the Court of Law with speculation and sensational remarks intended to taint the citizens of Los Angeles County who make up the jury pool," she said in a statement. "If the police would do their work investigating and providing their information to the District Attorney's Office for trial instead of spending time on their enormous public relations campaign to look good, we would all be better off."

Since 2007, a group of detectives has worked exclusively on identifying the killer. The big break in the case occurred last spring, when LAPD officials learned that a "familial search" of the DNA database by the California Department of Justice had come up with a convicted felon whose genetic blueprint indicated that he was a close relative of the suspect. A suspect soon became clear: the felon's father, Franklin, a 57-year-old mechanic.

It's unclear whether DNA evidence was a factor in linking Franklin to the two new cases.

The L.A. Weekly dubbed the killer the Grim Sleeper because of the lengthy, unexplained gap in the slayings.

Detectives revealed the additional victims during a previously scheduled community meeting with about 100 residents at Bethel AME Church in the Manchester Square neighborhood of South Los Angeles. An audience member, who might be a relative of one of the victims, asked about the new cases.

An LAPD source said the detectives had been working on the cases for months, well before they released images found in Franklin's possession in December. One of the victims was killed in the late 1980s, the other in the early 1990s.

Police have not linked any new homicides to Franklin based on the photos, but they have opened four missing-persons cases based on the released images.

Detectives have long been perplexed by the gap in the killings. For a while, they assumed the killer was in prison during this time. But that theory changed after Franklin was arrested. He was not behind bars during that period, and detectives said they now believe there were additional killings they don't know about. One reason for the gap might be that the LAPD had a task force looking into the earlier set of killings that disbanded in 1988. A new team picked up the case after the killings began again. That left 13 years in which the LAPD did not have a special team on the Grim Sleeper.

Franklin was charged with 10 counts of murder in the deaths of Debra Jackson, 29; Henrietta Wright, 35; Barbara Ware, 23; Bernita Sparks, age unknown; Mary Lowe, 26; Lachrica Jefferson, 22; Alicia Alexander, 18; Princess Berthomieux, 15; Valerie McCorvey, 35; and Janecia Peters, 25. He is also charged with one count of attempted murder, apparently stemming from the assault on the only victim known to have survived.