Updated

Authorities have arrested a suspect in shootings around the Las Vegas area that killed two homeless men, wounded a third and left another man working outside a convenience store with a gunshot wound — attacks that stirred fears in the homeless community.

Police said Las Vegas resident Joshua Castellon, 26, was taken into custody Friday on a federal weapons charge and faces state charges of murder and attempted murder.

Lt. Dan McGrath said Tuesday that forensic analysis connected the same revolver to all four shootings — three of which took place in an eight-hour period on Jan. 29. The last shooting happened Feb. 2.

"I wouldn't be able to explain a motive or why somebody does this, but he did not explain a motive," McGrath said, adding that Castellon was not homeless, but slept in his vehicle at times.

McGrath said a patrol officer approached Castellon on Feb. 8 when he was sleeping in his SUV, which matched the description of the one seen at the crime scenes. The officer interviewed Castellon.

Detectives on Feb. 15 contacted Castellon's estranged wife, who said she believed her husband had purchased a revolver in January, according to a federal complaint.

A day later, officers stopped Castellon, and he agreed to a formal interview. He told detectives that he had purchased a revolver to sell it to a "friend of a friend," according to the complaint.

McGrath said agents with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives arrested Castellon after the interview. Court documents do not list an attorney who could comment on Castellon's behalf.

The first victim was shot outside a convenience store in Logandale, about 60 miles (96 kilometers) north of Las Vegas. He was by himself when the gunman approached in a vehicle and fired several rounds, hitting him once. His wound was not life-threatening.

A few hours later, a gunman killed a man sleeping with a group of homeless people outside a mall. He died at the scene. Police were later notified that another homeless man had been taken to the hospital with a gunshot wound to the head. He survived.

The last victim, who was homeless, was found dead under a bridge Feb. 2. Surveillance video captured the suspect shooting the victim and running away.

McGrath said police have not found the weapon and believe Castellon may have sold it or had someone get rid of it.

McGrath said Castellon will be transferred to state custody after the federal case is resolved.

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This story has been clarified to show that one of the wounded victims wasn't homeless.