An armed man strolled to the back of an exercise class at a health club in suburban Pittsburgh on Tuesday night and then pulled out two guns and started spraying bullets, leaving four people dead, including himself, and injuring at least 10 others, authorities said.
A law enforcement official said two women and a man believed to be the shooter died at the scene Tuesday night and a fourth person died on the way to a hospital. The official wasn't authorized to comment on the investigation into the shooting and spoke on condition of anonymity.
Allegheny County police Superintendent Charles Moffatt said the shooter did not say anything before unleashing a burst of bullets.
"He walked right into the room where the shootings occurred as if he knew exactly where he was going," Moffatt said.
Three bodies were removed early Wednesday from the L.A. Fitness Center in Bridgeville, a community of about 5,000 residents not far from downtown Pittsburgh and the Pittsburgh International Airport.
A woman with a chest wound died at St. Clair Hospital, where two other female victims were in stable condition, spokesman Rich Sieber said.
Five victims arrived in critical condition at UPMC Mercy Hospital, and two women were listed in fair condition at Allegheny General Hospital, hospital officials said.
Joann Gazzam, who was taking part in the weekly Latin impact dance exercise class, saw the gunman walk to the back of the room near some weights, set down a bag and fumbled with it for a few minutes before coming up with what appeared to be two guns and opening fire, according to her sister, Debi Wozniak, of suburban Dormont.
Police say two guns were found at the scene, according to CBS Station KDKA, which first reported on the story.
Watch local video from CBS Station KDKA in Pittsburgh
Gazzam told Wozniak that the instructor was among those who appeared to have been shot, and that the gunman had killed himself.
"She told me, 'Debi, I seen everything. Oh, my God, I seen everything. I seen him pull out the guns,"' said Wozniak, who usually attends the class but was running late Tuesday and didn't make it.
Moffatt would not discuss a possible motive for the shooting, whose victims hadn't been identified.
"As you can imagine in a fitness club, they don't have identification on them," he said.
Loretta Moss, 44, of McDonald, said she was exercising on a treadmill when she heard a popping noise.
"I didn't pay any attention, and the next minute, people were screaming," said Moss, who had come to the gym Tuesday night for the first time in a couple of weeks. She said she then heard more pops.
"There was like a whole spray of them. I'd say about 15 altogether, and then people started screaming and yelling and started running out the building," she said.
"We laid down, and then after the last set of ... gunshots, we got up, and someone said run."
Moss said she then saw two young women bleeding, one shot in the leg and one in the shoulder. She said she checked on the pulse of the lady shot in the leg.
"She was screaming, 'It's burning, just please call the ambulance,"' Moss said.
Richard Walker of Tulsa, Oklahoma, who is in the area working on oil rigs, was playing basketball near the exercise room when he heard shots.
"The next thing I know, everybody's going, 'Run, run,"' he said. He said heard about 12 shots before he started moving and another eight or nine as he was leaving the building. He led a woman who had been shot in the thigh outside the building about 50 yards (46 metres) .
"She just kept saying, 'He's gonna kill me."' Walker said she didn't elaborate.
Brad Bolt of Dormont and Phil Fagan of Green Tree, both 20, were working out in a room next to the room where the shooting happened. They both said they heard about a dozen rapidly fired shots and Fagan said a girl came running out of the exercise room, yelling "Shots fired, call 911, get out."
The fitness centre, which opened last year, is in a strip mall called the Great Southern Shopping Center, where a few businesses were destroyed in a 2006 fire. The fitness centre said in a statement: "Each of us in the LA Fitness family are shocked and saddened by the senseless acts of violence that took place."
Allegheny County Chief Executive Dan Onorato, who was out of town on vacation with his family, was briefed by police after the shootings, which he called "an unspeakable tragedy."
"I ask everyone to keep those affected by this tragic event in their thoughts and prayers," he said.