The 'Grim Sleeper' Serial Killer: 7 Things to Know After Lonnie Franklin's Death

The victims were all young vulnerable Black women who lived in south Los Angeles and struggled with drug addiction. Their naked or partially clothed bodies were all dumped in the filthy neighborhood alleyways, left to rot under garbage and debris. They were shot at close range with a .25-caliber pistol, strangled, or both.

For years, their cases lacked justice — or even an arrest.

But in May 2016, following three months of testimony in Los Angeles Superior Court, Lonnie Franklin Jr., the "Grim Sleeper" serial killer who prosecutors say stalked L.A. for more than 20 years, was found guilty of murdering nine women and one teenager.

(PEOPLE senior writer Christine Pelisek, who broke the story of the Grim Sleeper, chronicled the case in her 2017 book, The Grim Sleeper: The Lost Women of South Central.)

After being sentenced to the death penalty, Franklin died in his prison cell at the age of 67 in San Quentin Prison on March 28, 2020. His cause of death was not released, but he had no signs of trauma on his body, California Department of Corrections and Rehabilitation spokeswoman Terry Thornton told PEOPLE.

Here are seven things to know about his terrifying murder spree that began in 1984.

1. He Was Married — and a Former Army Corporal

Franklin was a former corporal in the United States Army who also worked as a Los Angeles city trash collector and as a garage attendant at a Los Angeles Police Department (LAPD) station.

At the time of his arrest, he had been married for 32 years.

He was arrested in 2010 as he walked out of the mint green home he shared with his wife.

2. He Was a Sexual Predator "About Power and Control"

At his murder trial, prosecutors painted him as a sexual predator who killed women who "weren't submissive enough." "These crimes were about power and control," prosecutor Beth Silverman told the jury during her closing arguments.

"It is clear the defendant got pleasure from killing these young women because that's how they all ended up," Silverman said. "He definitely wanted to degrade these women by dumping their bodies like trash. He got off on that too, and that is why he did it over and over. It gave him gratification."

Franklin's longtime friend Ray Davis testified that Franklin's conquests were a common topic of conversation between them. Franklin took photos of various women and joked that he had names for all the girls in the photos depending on what their breasts looked like, Davis told the jury.

He also said that even though Franklin didn't smoke marijuana, he kept a supply on hand for his various girlfriends.

3. He Was Convicted of Murdering 10 People and Attempting to Murder Another

According to The Washington Post, Franklin was convicted in 2016 of the murder of 10 women — Debra Jackson, Henrietta Wright, Mary Lowe, Bernita Sparks, Barbara Ware, Lachrica Jefferson, Monique Alexander, Princess Berthomieux, Valerie McCorvey, Janecia Peters and 15-year-old teen, Princess Berthomieux.

His spree lasted from 1984 to 2007, but the apparent gap in his violent slayings — from the late 1980s to the early 2000s — gave him his nickname: The Grim Sleeper.

He was also found guilty of the attempted murder of Enietra Washington, who testified that Franklin shot her, sexually assaulted her and took a Polaroid picture of her before pushing her out of his car in 1988.

4. Police Believe He Murdered at Least Six More Women

After Franklin's arrest, detectives found more than 1,000 photos and videotapes of women and teenage girls in the former sanitation worker's garage and backyard camper.

In 2011, prosecutors announced their belief that Franklin allegedly killed at least six more women in addition to the 10 women he was convicted of murdering.

5. DNA Cracked the Case After Son's Arrest

The murder spree stumped detectives for more than two decades. It wasn't until the Los Angeles Police Department started its cold case unit that authorities realized the killer of seven women in the '80s was linked through DNA and ballistics to deaths in 2002, 2003 and 2007.

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However, the killer's DNA profile was not in CODIS, the national database for DNA. Franklin was finally caught in 2010 through familial DNA testing after his son, Christopher, was arrested for carrying a weapon in the summer of 2009 and had to give up a DNA swab.

Once it was determined that Christopher was related to the killer, detectives followed the elder Franklin to a pizza place in Buena Park. As Franklin finished his meal, a detective posing as a busboy collected a fork, two plastic cups, a plate and a pizza slice left by Franklin.

A few days later, DNA taken from the pizza slice came back as a match to DNA found on one of Franklin's victims.

6. He Kept Souvenirs of Victims

During the three-day search of Franklin's property, investigators allegedly found women's necklaces, rings, earrings and watches, as well as more than 500 photographs of various women — many of them naked or engaged in sex acts.

In one of Franklin's bedrooms, criminalist Rafael Garcia discovered an FIE Titan .25-caliber semiautomatic handgun, otherwise known as a "pocket pistol." It was later determined to be the gun used to kill Peters.

In a backyard garage, an LAPD firearms examiner found a Polaroid photograph of survivor Washington, who later testified against Franklin at his trial.

Also found was a photo of Peters. In the same envelope, they also found the school identification card of 18-year-old Ayellah Marshall and the Nevada driver's license of 29-year-old Rolenia Morris. Both women had been reported missing in February and September 2005, respectively. Both women were last seen in the vicinity of Franklin's home at 81st and Western Avenues in Los Angeles.

Their bodies were never found.

7. Victim's Stepmom Says They "Can Now Be at Peace," Following Franklin's Death

On March 28, 2020, Franklin was found unresponsive in his prison cell at 7:20 p.m. Prison medical staff rendered aid and summoned an ambulance. He was pronounced dead at 7:43 p.m.

He had no signs of trauma on his body, and Thornton, the prison spokeswoman, told PEOPLE at the time, adding that authorities didn't "know why he died" and that an autopsy was scheduled.

After Franklin's death, Diana Ware, stepmother of victim Barbara, told PEOPLE, "I won't say I'm pleased he died, but in the end, there was justice for all the bad things he did in his life. We can now be at peace."