Some were stunned to learn that the Joseph James DeAngelo Jr. ,who was arrested for being the Golden State Killer, once worked as a police officer. I wasn't because of a chilling encounter I experienced years ago.
Sacramento County Sheriff
Some were stunned to learn that the Joseph James DeAngelo Jr. ,who was arrested for being the Golden State Killer, once worked as a police officer. I wasn't because of a chilling encounter I experienced years ago.
Now playing
01:01
Tissue led to Golden State Killer case arrest
unmasking a killer new episode 1_00000419.jpg
unmasking a killer new episode 1_00000419.jpg
Now playing
00:54
How police found the Golden State Killer's DNA
unmasking a killer new episode 3_00002110.jpg
unmasking a killer new episode 3_00002110.jpg
Now playing
00:39
Cops believe Golden State Killer also did this
unmasking a killer new episode 4_00002524.jpg
unmasking a killer new episode 4_00002524.jpg
Now playing
00:45
Golden State Killer suspect's life behind bars
unmasking a killer new episode 2_00011012.jpg
unmasking a killer new episode 2_00011012.jpg
Now playing
01:15
Golden State Killer survivor shares her story
NBC
Now playing
01:36
Oswalt reacts to 'Golden State Killer' arrest
Sacramento County Sheriff Scott Jones announced Wednesday, April 25, 2018, they arrested Joseph James DeAngelo, 72. DeAngelo is believed to be the long-sought criminal known as the East Area Rapist or Golden State Killer, among other names.
Sacramento County Sheriff
Sacramento County Sheriff Scott Jones announced Wednesday, April 25, 2018, they arrested Joseph James DeAngelo, 72. DeAngelo is believed to be the long-sought criminal known as the East Area Rapist or Golden State Killer, among other names.
Now playing
02:10
Sacramento DA: We found needle in the haystack
unmasking a killer 2_00000000.jpg
unmasking a killer 2_00000000.jpg
Now playing
01:48
What we know about the Golden State Killer
unmasking a killer 3_00000711.jpg
unmasking a killer 3_00000711.jpg
Now playing
01:39
The Golden State Killer's psychological attacks
unmasking a killer 4_00001012.jpg
unmasking a killer 4_00001012.jpg
Now playing
01:37
The Golden State Killer took 'souvenirs'
unmasking a killer 5_00005516.jpg
unmasking a killer 5_00005516.jpg
Now playing
01:47
The Golden State Killer left behind evidence
unmasking a killer 6_00005827.jpg
unmasking a killer 6_00005827.jpg
Now playing
01:35
When did the Golden State Killer first strike?
CNN —  

When the suspected Golden State Killer drove into a Hobby Lobby parking lot in April, investigators were waiting nearby. As he walked into the craft store, it gave them a perfect chance to collect a secret DNA sample.

Police swabbed the driver’s side handle of Joseph James DeAngelo’s car, according to arrest and search warrants released Friday.

Authorities sent it for testing and matched it to semen recovered at some of the Golden State Killer’s crime scenes, the arrest warrant said.

The DNA collection at a public parking lot in Roseville, California, became a crucial turning point in the decades-old search for the suspect in the killings.

The documents unsealed by a California judge after a motion from news outlets provide a glimpse into detectives’ work in the days leading up to the suspect’s arrest.

Investigators collected the DNA on April 18. DeAngelo was arrested on April 24.

The 72-year-old has been charged in 12 killings, including the 1978 death of Katie and Brian Maggiore. Police say he committed a series of crimes attributed to the so-called Golden State Killer, also known as the East Area Rapist and the Original Night Stalker.

Car sample was one of several clues

The stop at the Hobby Lobby was just one of several ways investigators used to zero in on a suspect. Earlier this year, police tracked him down by comparing genetic profiles from genealogy websites to crime scene DNA, according to investigators.

On April 23, a day before his arrest, police say they collected multiple samples from a trash can outside DeAngelo’s home in Citrus Heights, a town 16 miles northeast of Sacramento. They had watched the home for three days, the warrant said.

Only one item inside the trash – a piece of tissue – provided enough DNA to run a test. Police matched it to evidence from the crime scenes, the documents said.

DeAngelo, has appeared in court twice, but has not entered a plea to the murder charges of the Maggiores.

He is also accused of killing Debra Alexandria Manning on December 30, 1979, while committing a rape and a burglary, according to the new charges. He allegedly killed Robert Offerman that same day while committing a burglary, according to court documents.

DeAngelo is also charged with killing Cheri Domingo while committing a rape and a burglary and killing Greg Sanchez while committing a burglary – both on July 27, 1981, a complaint says.

A public defender for DeAngelo had asked a Sacramento court to stop prosecutors from taking more fingerprints, DNA evidence and photos of the defendant’s body but a judge ruled that prosecutors could proceed.

Authorities have said they believe the Golden State Killer was responsible for killing a dozen people and committing at least 50 rapes in 10 counties in California between 1976 and 1986. For more than 40 years, investigators hunted for the man responsible for dozens of these crimes.

In recent years, there was renewed interest in the case. This year, a book and a series from HLN were released, in the hopes of shedding more light on the case.

Who is DeAngelo?

DeAngelo is a former police officer, Vietnam veteran and a mechanic.

In the early 1970s, he worked as a police officer in Exeter and Auburn, California. Authorities have said some of the alleged crimes of the Golden State Killer overlapped with DeAngelo’s time as a police officer.

He was fired from his law enforcement job in 1979 for shoplifting a can of dog repellent and a hammer from a drugstore.

He then lived what appeared to be a quiet life. He worked as a mechanic at the distribution center of a Modesto-based supermarket chain for 27 years until he retired last year, a spokeswoman for the company said.

Neighbors have said DeAngelo mostly kept to himself and sometimes yelled at people who got too close to his fence, but they said he had become a recluse in recent years.

CNN’s Dan Simon and Sony Hamasaki contributed to this report.