Ammar Asim Faruq Harris appeared Monday in Clark County District Court on murder and attempted murder charges in the Feb. 21 shooting and crash.
He initially told the judge Monday he wanted to plead guilty, but his lawyer said that would be a mistake, so Harris returned to court and entered not guilty pleas.
Harris, 27, is charged in the Feb. 21 pre-dawn killings of Kenneth Cherry Jr., a cab driver and cab passenger after police say he fired shots into Cherry's Maserati while driving a Range Rover on the Las Vegas Strip.
The Maserati crashed into a taxi cab that exploded, killing Michael Boldon, 62, of Las Vegas; and passenger Sandra Sutton-Wasmund, 48, of Maple Valley, Wash.
Harris fled the scene and was arrested a week later in Los Angeles.
Harris is charged with the murder of all three victims. He's also charged with the attempted murder of Freddy Walters, a passenger in the Maserati who was shot along with Cherry but survived.
Prosecutors are seeking the death penalty in the case. The trial is set for Sept. 9.
Harris previously was arrested in 2010 in Las Vegas on charges of pandering, kidnapping, sexual assault and coercion. The charges were dropped, but a witness re-emerged after Harris' arrest this year and a jury indicted him in April on three counts of sexual assault and one count of robbery related to the 2010 arrest.