A 20-year-old Arizona man has been charged with four counts of murder and one count of attempted murder after he allegedly shot five people randomly in the Phoenix area.

Iren Byers was arrested on Saturday after Mesa police identified him in video from near the scenes of several shootings on Friday and Saturday, according to NBC News.

One person was shot to death Friday in Phoenix, and four more shot Friday and Saturday in Mesa. One of those four survived. Mesa police said that Byers confessed to the shootings after his arrest.

Mesa Detective Brandi George said that Byers “has a lot of different motives” for the shootings, which were apparently random. Investigators also “suspect there may be some mental illness there,” she said.

Byers allegedly said he shot a 36-year-old woman in Mesa because “she made him mad” when he spoke with her, according to a probable cause statement. He reportedly said he shot her in the face and then “shot her another time because she wasn’t dead yet.”

The woman didn’t die and is undergoing surgery for serious injuries, George said. Police found her shortly after midnight Saturday morning.

The Phoenix victim was shot dead just before 3 p.m. on Friday. According to probable cause statement, Byers said he shot him “because he was abusing fentanyl, which he did not like since [Byers’] brother abused the drug too.” Byers reportedly told police the man “was not armed and was not a threat to him” and said he got on a bus and left the scene after the shooting.

The Mesa fatalities were a 41-year-old man found dead at about 10:30 p.m.; a 41-year-old man found dead at about 1 a.m. Saturday; and a third person believed to be an adult man found dead at about 2 a.m.

According to the probable cause statement, Byers told police he shot the two 41-year-old men because they discussed fentanyl with him. He shot the third man because “he was homeless and not from around here,” the statement says.

Byers added that he didn’t call for medical help because none of the victims deserved it, the statement said.

Police saw Byers on videos near all of the shooting scenes and arrested him at his home in Mesa, initially charging him with trespassing on railroad tracks. Once in custody, however, Byers confessed to all the shootings and told officers where to find the clothes he was wearing and the gun he used. They found those items at his home after obtaining a search warrant.

Byers is being held without bond.

His victims have not been publicly identified.

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[Featured image: Iren Byers/City of Mesa Police Department]