Police Identify Shooter in Colorado Shooting 5:42
(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 revealed at a news conference by Boulder Police Chief Maris Herold, who did not reveal a possible motive for the bloody event.
A search of the suspect's home in the Denver suburbs showed the presence of other weapons, a senior law enforcement source said Tuesday.
The weapon used in the attack was a modified AR-15-style pistol with a prosthetic arm, according to the source.
Authorities believe that 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 count of attempted murder, according to his arrest warrant.
His first court appearance is scheduled for Thursday at 8:15 a.m. (10:15 a.m. ET), according to online records from the Colorado Judicial Branch.
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The court order describes Alissa as a man armed with an assault rifle or "black AR-15" and wearing a "tactical" or "armored" vest.
The suspect had "removed all his clothes and was wearing only shorts" when he was arrested, according to the affidavit.
Outside the store, the document says, Alissa did not tell police if there were any other suspects, but did ask to speak to her mother.
Using law enforcement databases, according to the affidavit, investigators determined that Alissa had purchased a Ruger AR556 pistol on March 16.
Boulder County District Attorney Michael Dougherty said Alissa is a resident of Arvada, between Boulder and Denver, who has "lived most of her life in the United States."
Ahmad Al Aliwi Alissa was arrested after the mass shooting.
The suspect would have suffered mental illness and harassment, says his brother
The alleged attacker's brother told CNN that he believes 21-year-old Ahmad Al Aliwi Alissa suffered from mental illness and was bullied in high school for being Muslim.
His brother, Ali Aliwi Alissa, 34, said Tuesday that the harassment included making fun of his younger brother's name and may have contributed to his being "antisocial."
Around 2014, Alissa felt being followed and persecuted and became increasingly "paranoid," said her brother, who lives with him.
At one point, he put duct tape over his computer camera to block out anyone he believed was following him, he said.
Here's what we know about the Boulder, Colorado shooting that left 10 dead
At least 10 killed in shooting in Boulder, Colorado 2:38
"He always suspected that someone was after him, that someone was chasing him," Ali Alissa said.
“We watched him closely when he was in high school.
He would say, 'someone is chasing me, someone is investigating me', and we would say, 'come on man, there's nothing.'
... He was isolating himself.
Authorities have not disclosed a potential motive in the case.
Ali Alissa said her brother was not a very political or particularly religious person.
He added that he had never heard him threaten violence.
"Everything surprised me, I never thought I would do something like that, I never thought I would kill someone," he said.
“I still can't believe it.
I am really sad for the lives that ended, and I feel sorry for all those families… We lost a brother even if he is the murderer.
The shooting in Boulder, Colorado, is the seventh mass shooting in 7 days in the United States
Suspect of mass shooting in Colorado is arrested 6:58
He said he never knew Alissa had a gun.
"He does not carry any weapons of any kind," he said.
"We never saw weapons on him, the only weapon in his hand is the knife he uses for cooking."
He said he doesn't know why his brother went to King Soopers on Monday, and Alissa said he and another brother were questioned by police and that authorities searched their home until 5 a.m. Tuesday.
"They searched every corner, every piece of clothing."
He added that his family emigrated from Syria in 2002 and has lived in the Arvada area since 2014.
Ahmad Alissa attended Arvada West High School from March 2015 to May 2018, according to a spokesperson for Jefferson County Public Schools.
Alissa was convicted of assault in 2018
Alissa was sentenced to one year of probation and 48 hours of community service after being convicted of third degree assault in 2018 for an incident that occurred the previous November, according to the Colorado Bureau of Investigation database.
The case stemmed from an incident in which Alissa, then 18, was accused of attacking a classmate at Arvada West High School.
A report from a police officer included in the case file says that Alissa "got up in (a) classroom, walked up to (the) victim and hit him on the head."
Alissa "got on top of (the victim) and punched him in the head several more times," the report says, adding that the victim "had bruises, swelling and cuts on (the) head, as well as pain."
"No witnesses were able to see or hear any reason" for the attack, and Alissa said the victim "had taunted him and called him with racial slurs weeks earlier," the officer wrote.
With information from Ray Sanchez, Blake Ellis and Amir Vera
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