Here's what we know about the Boulder, Colorado, mass shooting suspect
By Ray Sanchez, Paul Murphy, Blake Ellis and Amir Vera, CNN
Ahmad Al Aliwi Alissa was identified by authorities Tuesday as the gunman who opened fire at a King Soopers grocery store in Colorado, killing 10 people, including a Boulder police officer.
The name of the 21-year-old suspect, who is in custody, was released at a news conference by Boulder Police Chief Maris Herold, who did not disclose a possible motive for Monday's bloodshed.
A search of the suspect's suburban Denver home turned up other weapons, a senior law enforcement source said Tuesday. The weapon used in the attack was an AR-15-style pistol modified with an arm brace, according to the source.
Authorities have said they believe Alissa was the only person involved and that there was no additional threat to the community.
The suspect has been charged with 10 counts of first-degree murder and one charge of attempted murder, according to his arrest warrant. His first court appearance is scheduled for 8:15 a.m. (10:15 a.m. ET) Thursday, according to Colorado Judicial Branch online records.
The warrant described Alissa as being armed with either an assault rifle or "black AR-15" and wearing a "tactical" or "armored" vest. A senior law enforcement source told CNN on condition of anonymity the shooter used a Ruger AR-556 pistol, modified with an arm brace, and was also carrying a 9 mm handgun, according to the source.
The suspect had "removed all of his clothing and was dressed only in shorts" when he was taken into custody, the affidavit said. Outside the store, the document said, Alissa wouldn't tell police whether there were other suspects, but he did ask to speak to his mother.
Using law enforcement databases, the affidavit said, investigators determined Alissa had purchased a Ruger AR556 pistol on March 16.A law enforcement official told CNN Alissa was not previously the subject of any FBI investigation and said it appears nothing in the federal system would have prohibited Alissa from buying a firearm.