A gunman opened fire at a Walmart store in Chesapeake, Virginia, on Tuesday night. Here’s what you need to know.

The victims: At least six people were shot dead inside the Walmart. Four victims from the shooting are in area hospitals with unknown conditions, according to Chesapeake Police.

The shooter: The shooter is dead, police said. While police declined to identify the suspect, saying next of kin had not yet been notified, investigators believe he was an employee of the store who opened fire on other employees in a break room, a law enforcement source told CNN. Officials believe the suspect at some point turned the gun on himself, according to the source.

The timeline of events: Chesapeake Police Chief Mark Solesky provided a timeline of events. The police dispatch center received the first call at 10:12 p.m. on Tuesday night. Officers arrived on scene within two minutes at 10:14 p.m. and entered the store two minutes later at 10:16 p.m. They declared the scene safe by 11:20 p.m.