Authorities in San Diego arrested a man this morning who is suspected of having attacked five homeless men, killing three, in a series of incidents that began July 3. Last week in Phoenix, meanwhile, a woman who was shot in a random attack on June 12 died of her injuries; six others have died from wounds sustained in that and several other random and seemingly connected shootings.

The victims in the San Diego incidents have all been homeless men sleeping alone who appear to have been attacked during early-morning hours. All sustained “major upper body wounds” and fires were set at two of the crime scenes. The suspect in custody was detained not long after another victim was found alive but wounded this morning; officers on patrol shortly thereafter saw and arrested an individual who resembled a man whose image was captured on a convenience store surveillance video in the area of the first attack. His identity has not yet been released.

On Thursday, police in Phoenix released a composite sketch of the man believed to have been involved in eight recent shootings dating back to March 17. The incidents involve victims who were “outside or in a vehicle when shot in or near residential neighborhoods during hours of darkness,” a police spokesman says. Said the city’s police chief in a statement calling on residents to provide information to authorities: “Someone out there knows who did this.”