A gunman carrying homemade explosives shot dead two people at a popular shopping mall near Washington before killing himself.
Police identified the gunman yesterday as a 19-year-old from the nearby city of College Park, but had no word on his motive nor whether he had any ties to the two people he shot and killed in a skate shop.
The gunman, identified as Darion Marcus Aguilar, opened fire with a shotgun in the shop at the mall in Columbia, Maryland, about 32 kilometres west of Baltimore, on Saturday before apparently killing himself, police said.
Aguilar, who lived with his mother, arrived at the mall by taxi about an hour before the shooting began, Howard County Police Chief Bill McMahon told a news conference.
He used a 12-gauge shotgun, and fired six to eight shots, killing Brianna Benlolo, 21, also of College Park, and Tyler Johnson, 25, of Mount Airy, Maryland, police said.
Both were employees of Zumiez, a skate shop where the shooting took place. A third person was also injured.
Police arriving at the scene found Aguilar's body and his backpack filled with crude explosives, McMahon said, adding that officers were initially concerned he had booby-trapped himself.
The mall of about 200 stores is a favoured weekend destination for young and old alike. First responders were alerted to mid-morning gunfire at the mall by an emergency police call indicating shots had been fired inside the two-storey centre.
Badly shaken shoppers described how they fled in panic or cowered in doorways. Some made frantic calls to loved ones, as the United States reeled from the latest in a slew of gun-related rampages.
Howard County General Hospital said all five injured shooting victims had been treated and released. One had a gunshot wound to a foot.
The Baltimore Sun newspaper said shoppers reported hearing gunfire before fleeing the mall, home to several department stores such as Sears, Lord & Taylor, Macy's and Nordstrom.
"In today's world that we live in, when you hear gunshots, you run. There's nothing else to do," a store employee told CNN.
The most notorious shooting in recent US history took place in Newtown, Connecticut, in December 2012, when a young gunman opened fire in a school. In 10 minutes, the 20-year-old shot and killed 26 people before taking his own life.
That attack briefly reignited the US gun control debate, triggered every time there is a major shooting, although attempts to pass tougher laws have made little headway in Congress.
Additional reporting by Reuters