Ahmad Al Aliwi Alissa, of Arvada, Colorado, was taken into custody about 50 minutes after the shooting was reported. He was charged with 10 counts of first-degree murder as well as one count of attempted murder for allegedly shooting at a police officer who was not hurt.
At Thursday's court appearance, prosecutors said additional charges are expected in the next few weeks.
Defense attorneys said more time is needed to assess Alissa's mental health.
Alissa was held without bail and the judge ordered a status conference to take place in about 60 to 90 days.
A possible motive has not been released. According to the arrest warrant affidavit, the suspect bought a Ruger AR-556 pistol on March 16.
The other victims were identified as: Denny Stong, 20; Neven Stanisic, 23; Rikki Olds, 25; Tralona Bartkowiak, 49; Suzanne Fountain, 59; Teri Leiker, 51; Kevin Mahoney, 61; Lynn Murray, 62; and Jody Waters, 65.
As Talley's body was escorted from the coroner's office to the funeral home on Wednesday, fellow officers gathered on roads and overpasses to show their support.
Talley's handcuffs were used to transport Alissa to jail, Boulder police said.
"Though this was a small gesture, we hope it is the start of the healing process that so many of us need at this time," the police department tweeted.