Kilcoyne, who headed the investigation, said it was the second time a query was run for familial connections in the "Grim Sleeper" case. From the DNA matches, a tight circle of law enforcement officers zeroed in on Franklin based on the suspect's residence, location of the victims, his race and age.
Familial DNA database searches have come under fire from privacy and civil liberty advocates, who argue, among other things, that they put more minorities, who are disproportionally represented in the database, in an at-risk group.
The Supreme Court has upheld the constitutionality of familial DNA sample collection and searches. Brown said the office of the attorney general will be in court again next week defending the technique, and raised the possibility of more legal challenges.
The killings of 9 young black women and one man, beginning in 1985, have all been blamed on the "Grim Sleeper." Franklin has not been charged in the shooting death of 36-year-old Thomas Steele, but police said they believe his death is connected to the other killings.
The cluster of killings stopped in 1988, but 14 years later police said they linked new murders to the same man. The nickname "Grim Sleeper" came from the long lull between killings. The most recent murder happened in January 2007.
Los Angeles Mayor Antonio Villaraigosa praised law enforcement officials for their "exhaustive detective work" in the past 25 years that led to nabbing the suspect. More than two dozen investigators worked to find the "Grim Sleeper."
"I'm proud to announce that this terror has finally come to an end," Villaraigosa said at a news conference.
Relatives of the victims who were in attendance said they were elated and thankful that the police finally brought the alleged killer to justice.
Police closed off the block on 81st Street in South Los Angeles where Franklin lived Wednesday and the arrest was made.
Residents said they were shocked. Neighbor Donna Harris said she has known Franklin, a retired mechanic, for nearly 20 years, and that he was supposed to fix her car that morning.
"Everybody on the block, we all knew if anything was happening with anybody's cars, he was always there for us. Especially the ladies," Harris said. "Even if we weren't at home, instead of calling Triple-A, he would help."
Franklin was reportedly a mechanic for a Los Angeles Police Department station near the center of the murder spree in the 1980s.
Though Harris counted Franklin as a friend, she said the news was frightening.
"It frightens me to know that somebody like that was that close," Harris said. "I don't want to believe it's true, [but] if he did what he's been accused of, God judged him for that."
Franklin has a criminal history dating back to 1989, according to public records. His four previous convictions include charges of a misdemeanor battery and assault, as well as two charges for stolen property -- one of which he served jail time for.
With these latest charges, he could face the death penalty or life in prison without possibility of parole.
A handful of detectives, headed by Kilcoyne, have been working full-time on the case for years, determined to find the "Grim Sleeper."
All the slayings have been connected to the same 25-caliber handgun, and matched to the same DNA, usually saliva taken from the victims' breasts.