A man believed to have killed two people with a shotgun at a Maryland mall before shooting himself also had improvised explosives made from fireworks, police said.
The suspected shooter had been tentatively identified, but police had not released his name as of late this evening.
At a news conference this evening, Howard County Police Department Chief Bill McMahon said police were still investigating a possible motive, but they were sure the incident was over.
"We are very confident that it was a single shooter, that there is no other shooter in the mall," McMahon said.
All three of the dead were found in the Zumiez store, and Howard County police identified the two believed to have been shot by the gunman as Brianna Benlolo, 21, of College Park, Md., and Tyler Johnson, 25, of Ellicott City, Md. Both were employees of the skateboard store.
"All of the activity took place at one time, in one store," McMahon said.
Law enforcement sources told ABC News that one scenario being investigated was that it was a domestic dispute involving a man, his estranged girlfriend, and her boyfriend.
Before confirming that, law enforcement was trying to make sure they have the identities of the dead correct, and trying to rule out any other possibilities, sources said.
McMahon said at the news conference that it was too early to speculate on the motive.
"We have no knowledge of that yet," McMahon told reporters of the suspected domestic dispute motive. "The Howard county police department is investigating the shooting incident and do not know yet what caused the shooting incident."
One of the three dead was found near a gun and ammunition, and was believed to have likely been the shooter, police said.
"A search of the shooter's bag found inside the store revealed two crude devices that appeared to be an attempt at making explosives using fireworks," Howard County police said in a statement tonight.
McMahon said the gun used was a shotgun, but he did not know how many shots were fired.
Aside from the three dead, five people were injured, one who was shot in the foot and the others who hurt themselves as they were trying to get away, McMahon said.
Police started getting 911 calls about a possible shooting at the mall at around 11:15 a.m., and it was immediately put on lockdown, McMahon said. Police were reportedly on the scene within two minutes of the calls.
Witnesses described hearing five or six pops, which sparked panic.
"I didn't know what I thought it was and then I saw the other people like starting to run and then there were these others, next to me, like that's definitely a gunshot, so I just took off running for the entrance," shopper Christine Cruz said.
Elizabeth Braun, 31, of Westminster, Md. told ABC News she realized something was wrong when she started to see people running panicked.
"I was actually in the mall about to make my purchase, I saw people running into the store," said Braun. "The sales clerk was like 'let's go'"
Braun said she hid with at approximately 50 other people in a Victoria's Secret storage room to stay out of harm's way. Employees closed the store's metal gates to seal off the interior entrance that connected to the mall.
"Mostly [it] was pretty calm, mostly people were trying to figure what was going on," Braun said of the people in the storage room.
Braun said entered through the food court around 11 a.m. and thought the mall seemed more empty than usual.
"I thought I must have gotten there here really early," she said.
"It's one of the two malls you would go to," if you live in the area, she said. "I guess everyone is in this naive state of mind that this would never happen to them."
The two-story mall is about 40 minutes outside Washington, D.C., and has a movie theater in addition to a number of shops.
ABC News' Mike Levine contributed to this report.