"My niece said a couple bullets went past her head and [the gunman] leaned down, straddled her and shot her in the shoulder," he said.
Sources close to the investigation told ABC News that multiple guns were used in the attack, including one that was registered to Sodini.
Collier Township Police Chief Tom Devin told reporters that he believed the shooter committed suicide at the scene.
Moffat said that the man did not say a word upon entering the gym nor when walking into the dance studio.
"He walked right into the room where the shootings occurred as if he knew exactly where he was going," he said.
The floor was littered with shell casings and blood, according to surviving witnesses.
A local hospital treated five women who were shot multiple times, reported WTAE. Four have been upgraded to "serious" condition and one has been released from the hospital, Moffatt said.
LA Fitness gym staff told WTAE that it was a busy night health club at the time of the shooting, with about 100 people inside. Witnesses said people inside the gym took off running amid the gunshots.
Lauren Dooley, 26, told the Pittsburgh Post-Gazette, that she had been running on a treadmill, listening to her iPod when the chaos broke out.
"I saw people flying off the treadmills, hitting the ground" for cover, Dooley said. "We crawled through the fire escape, and I sprinted out the back."
"I turned around there was one girl shot in the thigh and one girl shot in the back," Branson Holly, a witness inside the gym at the time of the shooting told WTAE. "I'm still shaken because I was in spinning class and it could have been my class."
Many heard the sounds of gunfire, others actually saw shots being fired in the darkened room.
"The lights were off, and I could see flashes in the dark," said Jared Frederick, a witness.
Debi Wozniak told The Associated Press that she is normally a regular at the weekly Latin impact dance exercise class. She says she missed the class Tuesday, but her sister, Joann Gazzam, had attended.
Gazzam told Wozniak that a man came in through the glass double doors, walked to the back of the room and set down the bag. She said he began looking through his bag and pulled out and began shooting.
"She told me, 'Debi, I seen everything, oh my God, I seen everything. I seen him pull out the guns,"' Wozniak said.
ABC News' Emily Friedman and Stephen Splane contributed to this report.