Prosecutors obtained a warrant the day after the shooting for Harris' arrest on three murder, one attempted murder and several shooting charges. Authorities obtained a federal warrant Monday enabling the FBI to join the search in other states.
Earlier Thursday, Las Vegas police revealed they had found and talked with all three women who were in the SUV with Harris during the shooting-including Tineesha Lashun Howard, a woman police had identified Tuesday as a "person of interest" who might be in danger.
Las Vegas police also sought to stop the circulation of several photos the department issued during their search for Harris. Police said they depicted people not connected with the case.
Police wouldn't release the names of the other female passengers in the SUV. Capt. Chris Jones said none of the three women had been charged with a crime. Police were concerned about their safety, he said.
Howard, a 22-year-old from Miami with a history of prostitution arrests who also uses the names Yenesis Alfonzo or Yani, was found late Wednesday, several hours after boarding a bus in Los Angeles. Police have not identified the city where she was found.
Steiber called the discovery that Howard left Los Angeles "one of the factors" that led investigators to find Harris in Studio City.
Police later searched the Studio City apartment, and Steiber noted that the investigation was not finished.
"We have captured Ammar Harris," the police lieutenant said. "This is an open and ongoing investigation. This is not closed."
Clark County District Attorney Steve Wolfson said Thursday that anyone who helped Harris elude police for a week could still face criminal charges.
Harris was arrested last year in Las Vegas in a 2010 prostitution case using the name Ammar Asim Faruq Harris. He was charged with robbery, sexual assault, kidnapping and coercion with a weapon, and police sought charges of pandering by force and felon in possession of concealed weapon. Court records show that case was dismissed last June.
Harris was convicted in South Carolina in 2004 of felony possession with intent to sell a stolen pistol and convicted that same year in Atlanta of a misdemeanor marijuana possession charge.