As many as 14 people have been shot dead in a murderous three-minute shooting rampage inside an upstate New York civic association building that caters to immigrants, according to federal and state authorities.
The gunman was identified by some police sources as Jiverly Voong.
According to Binghamton Police Chief Joe Zikuski, the gunman entered the one-story American Civic Association in downtown Binghamton at 10:31 a.m. today and began his shooting spree.
By 10:33 a.m., the shooting was over and 14 people -- including the gunman -- lay dead, the chief said.
At least four people were listed in critical condition. Earlier, sources said as many as 26 people were wounded.
Officials who initially said Voong worked for IBM and had been discharged later said they believed that was false. At IBM, there was no record that Jiverly Voong ever worked there.
"We have no idea what the motive is," Zikuski said.
Police were interviewing Voong's family members and executing a search warrant at his home in an effort to establish a motive. Officials were seen removing a gun rifle case, two hard drives, two briefcases and two brown paper bags from the home.
Officials said Voong entered the civic association armed with two pistols -- a 9 mm and a .45 caliber handgun. A satchel around the gunman's neck carried high capacity magazines, a survival knife and a flashlight, according to police.
Voong backed his car up to the rear door of the building.
"Obviously, it was premeditated. He made sure nobody could escape," Zikuski said.
Voong then headed to the front where he allegedly began executing people.
Voong, 41, also known as Linh Phat Voong, was from Johnson City, N.Y.
Police refused offically to identify the shooter, though sources said it was Voong.
He allegedly burst into the civic center wearing a bright green nylon jacket and dark-rimmed glasses and promptly shot two female receptionists.
One woman died, but the second woman survived.
"She pretended she was dead," Zikuski said. As the gunman headed for a room off the reception area, "she crawled underneath the desk and sometime after that called us," he said.
Most of the people killed or injured were in one classroom taking a citizenship exam.
The police chief said 37 people were safely removed from the building, 26 of whom barricaded themselves in the building's boiler room.
Police arrived just two minutes after the receptionist called 911. Though the shooting lasted only minutes, it took police three hours to make sure the shooter wasn't still alive and laying in wait for more victims.
Zhanar Tokhtabayeva, a 30-year-old from Kazakhstan, told the Associated Press she was in an English class when she heard a shot and her teacher screamed for everyone to go to the storage room.
"I heard the shots, every shot. I heard no screams, just silence, shooting," she said. "I heard shooting, very long time ... and I was thinking, when will this stop? I was thinking that my life was finished."
When the carnage was over, Voong's body was found on the first floor with a hunting knife jammed into the waistband of his pants.
"He shot those people? No. No," said a woman who identified herself as Voong's sister, but would not give her name when reached by ABC News.com.