The motive for the mass shooting at a grocery store in Boulder, Colorado that killed 10 people, including a police officer, on Monday remains unknown after authorities arrested the suspected gunman.
Boulder Police Department Commander Kerry Yamaguchi said during a press conference that investigators were still searching for a motive after the alleged shooter opened fire at a King Soopers store, per CNN.
Officials offered few details about the suspected gunman, whom they said was given medical treatment after he was arrested. The authorities did not disclose what he was treated for, though they reported that he was the only person who survived injuries in the shooting.
“We will work around the clock to get this accomplished,” Boulder Police Chief Maris Herold said of the investigation.
A source in law enforcement told CNN that the suspect had used an AR-15-style rifle.
Herold identified the slain officer as Eric Talley. The names of other nine victims have not yet been announced.
The shooting comes on the heels of another gun massacre at three spas in the Atlanta, Georgia area last week, which led to eight deaths. Six of the victims were women of Asian descent. Authorities have not reported a possible motive for those attacks.