A man has been arrested and charged in a serial shooting and robbery case that killed two people and wounded six others in Los Angeles over a three-year period, police announced Monday.

Patrick Watkins, 51, was arrested Thursday on two murder charges and 25 charges of attempted murder in the "Western Bandit" case, named for the street where some crimes occurred.

It wasn't immediately clear whether Watkins has an attorney. He was expected to have his first court appearance on Tuesday.

The latest of 23 crimes linked to the case was the fatal shooting of a 56-year-old man as he walked his dog on Dec. 8, 2014. The other killing linked to the case is the November 2011 fatal shooting of 32-year-old Cassidy Vickers.

Los Angeles Police Chief Charlie Beck said the same gun was linked to all the cases and was recovered during Watkins' arrest.

Capt. William Hayes, who heads the department's elite Robbery Homicide Division, said the crimes were quickly linked to the same case because of the description of the man committing them and the unusual method of operation -- all the victims in the case reported being shot at before they were robbed.

"That's very unusual," Beck said. "And it speaks to the dangerous nature of this individual and why he so richly deserves to be in prison."

Police said a forensic test on a piece of DNA evidence collected from one of the crime scenes was the key to cracking the case.