"The terror began and spread throughout the streets of South Los Angeles," the mayor said at a news conference. "One man preyed on the innocent, and stole the lives of women living in some of our toughest neighborhoods."
Lonnie Franklin Jr., 57, was charged Wednesday with 10 counts of murder, one count of attempted murder and special circumstance allegations of multiple murders that could make him eligible for the death penalty if convicted.
Arraignment was expected later Thursday. Many of his alleged victims were prostitutes, and all but one were women.
Police Chief Charlie Beck said a special detective team formed in 2007 made the investigation the largest ongoing case in his department.
Porter Alexander, the father of victim Monique Alexander, said he thought police had given up and doubted he would live to see an arrest.
"It shows today that the long arm of the law still prevails," Alexander said, adding that he was humbled and grateful.
To many of his neighbors and customers, Franklin was just a friendly mechanic who often stopped to chat as he tinkered on cars in the front driveway of his mint-green house on 81st Street.
But after police alleged he was the serial killer, other neighbors recalled traits that suddenly seemed chilling.
Some neighbors said Franklin made no secret of enjoying the company of sex workers, who he would often bring back to a camper parked in his backyard filled with old cars and junk.
Tasha Cole said he would point out different prostitutes when they would walk by and talk about them disrespectfully.
"He knew all of them and their stories," she said.
Another neighbor, Sherwood Howard, said Franklin would show off nude photos he took of the women from the neck down and talk about his exploits. He kept the pictures in the garage.
"He'd go and mess with women all night long," Howard said. "We knew he was kind of weird, but he was a regular person. We never suspected he was killing them."
Detectives have spent years investigating the slayings that occurred between 1985 and 2007. The attacker was dubbed the "Grim Sleeper" because he apparently took a 14-year hiatus from his crimes, from 1988 to 2002.
The victims were shot, strangled or both, usually after some kind of sexual contact.
The break in the case came after Franklin's son was arrested and swabbed for DNA, said Donnell Alexander, brother of victim Monique Alexander, who was given a briefing on the case by robbery-homicide detectives.
Using a controversial technique known as a familial DNA search, the sample was flagged as similar to evidence in the serial killings, leading police to investigate relatives of Franklin's son.
Detectives later swabbed a cup used by Lonnie Franklin Jr. at a restaurant and confirmed his DNA matched that in the serial killings, police said.
The following year, he moved to the sanitation department, where he worked a number of jobs before becoming a refuse collector. He left city employment in 1989.
Franklin's house is nestled amid a row of stucco homes, most of them single-story, in this working-class community where many neighbors know each other. The house is within blocks of the alleyways where some of the victims were dumped.
The initial killings occurred during a violent period in parts of Los Angeles, when many young women were falling prey to crack cocaine and other drug addictions. As many as 30 detectives investigated the slayings in the 1980s but exhausted leads within a few years.