The victim, 79-year-old Euvaldo Sisneros, had been hospitalized since the attack but died of his injuries Tuesday afternoon, police said.
Sisneros was taking his afternoon walk in the 2800 block of Humphrey Avenue around 3:40 p.m. on June 16 when a man approached him from behind. The man knocked Sisneros to the ground and began repeatedly striking him on the head and upper torso.
Before running away, the man picked up Sisneros' head and drop-kicked it, Richmond police Chief Chris Magnus said. He then left Sisneros unconscious on the street, police said.
Sisneros, a retired machinist, had lived in the neighborhood for most of his life. At a news conference the day after the attack, Francis Sisneros, the victim's wife of 60 years, described her husband as a good-hearted person who would never hurt anyone.
Witnesses helped police create a sketch of the suspect and, on June 17, an officer spotted Villalobos, whose face matched the sketch, police said.
Based on information gathered during the investigation, police are convinced that Villalobos was the attacker, Lt. Mark Gagan said.
Jewett, who filed the charges against Villalobos Wednesday morning in Contra Costa County Superior Court, said Villalobos had a "substantial history of violence," but that investigators still have no idea what prompted the attack.
"This guy clearly has some mental and emotional issues that need to be addressed," Jewett said.
Villalobos will likely be arraigned Wednesday afternoon in Contra Costa County Superior Court in Richmond.