One of the suspects, Dale Hausner, has even suggested that the "Baseline Killer," another suspected serial killer, was responsible for some of the killings, the Arizona Republic reported.
"I wasn't there for any killings," Hausner reportedly told police. "I did not drive the car for any killings. I did not pull the trigger on anybody ... I'm not a murderer. I don't kill people."
Samuel Dieteman admits being on the scene of at least two shootings, but says Hausner took him by surprise when he rolled down the window and fired, the newspaper reported. He said that when Hausner ordered him to shoot someone he deliberately aimed high, the report said.
Hausner faces seven counts of first-degree murder, while Dieteman, who was living in Hausner's apartment in Mesa, has been charged with two killings.
Seven people were shot dead and at least 18 wounded in a series of drive-by shootings that began in June 2005. Police believe that the suspects targeted people who were out alone, especially those who appeared to be transients.