Aaron Juan Saucedo, 23, entered a not-guilty plea through his attorneys in Maricopa County Superior Court on Thursday to 20 felony counts. Saucedo was not present at the arraignment, having waived his right to appear as well as a reading of charges.
Prosecutors say Saucedo was behind 12 serial street shootings that left nine people dead between August 12, 2015 and July 11, 2016.
Last week, a Maricopa County grand jury charged Saucedo with 20 felony counts: eight counts of first-degree murder, two counts of aggravated assault, discharging a firearm, endangerment, six counts of drive-by shooting and two counts of attempted murder.
Saucedo was arrested in April for allegedly shooting dead his mother’s boyfriend, 61-year-old Raul Romero.
On May 5, Saucedo pled not guilty to that charge, telling the courtoom, "I'm innocent."
Three days later, police announced at a press conference that Saucedo was the suspect in the Serial Street Shooter case. Saucedo, for his part, has been in custody since his April 19 arrest for the killing of Romero in August 2015.
Police believe Romero's murder in 2015 was the first of the string of shootings for which they hold Saucedo responsible.
Prosecutors say other victims include Jesse Olivas, 22, on January 1; Diego Verdugo-Sanchez, 21, on April 1; Manuel Castro Garcia, 19, on June 10; and Stefanie Ellis, 33, and her daughter Maleah, 12, on June 12.
At least six of the victims were shot and killed in the Maryvale neighborhood of west Phoenix.
Saucedo's next court date is on August 16.