San Diego Police Chief Shelley Zimmerman speaks at a press conference on the killings earlier this week. Photo: AP

23-year-old Dionicio Derek Vahidy died in San Diego on Sunday after being set on fire while sleeping outside, becoming the third victim allegedly killed this month by the same man targeting homeless people, KSWB reports.

On Thursday, police arrested 36-year-old Anthony Alexander Padgett, who they say assaulted Vahidy and three other homeless men over the course of four days. From the Associated Press:

The violence began July 3, when police found the badly burned remains of Angelo De Nardo between Interstate 5 and train tracks. The 53-year-old died before his body was set on fire.

The next day, officers responding to a 911 call found Manuel Mason, 61, with life-threatening injuries to his upper torso. A few hours later, police discovered the body of Shawn Longley, 41, who bled from the upper torso and died.

Then on Wednesday came the attack on Vahidy.

According to The L.A. Times, Padgett was found guilty of a similar crime in 2010 after setting a sleeping friend on fire, leaving the man with burns on over 20 percent of his body. Padgett himself was reportedly homeless at the time.

“These evil acts of violence are some of the worst that I have seen in my 34 years in law enforcement,’’ said San Diego Police Chief Shelley Zimmerman at a press conference earlier this week. “This killer has targeted some of our city’s most vulnerable citizens while they are asleep.’’