A senior law enforcement official told ABC News that 13 people were shot dead and 26 were wounded.
Voong entered the civic association armed with two heavy caliber automatic pistols ? a 9 mm and a .45 caliber handgun. He carried a bag filled with high capacity magazines, a survival knife and a flashlight, according to police.
Officials said Voong backed his car up to the rear door of the building to block any escape before he went to the front of the building and started to execute people.
Voong, 41, also known as Linh Phat Voong, was from Johnson City, N.Y. He allegedly burst into the civic center wearing a bright green nylon jacket and dark-rimmed glasses. Upon entering, Voong shot and killed the receptionist and then two other people. He then headed for another room of the civic association and opened fire again.
When the carnage was over, Voong's body was found on first the 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.
She said her brother went to take classes today at the civic association and that she had not heard from him since. She said she did not know that he was involved in the shooting.
"I'm going to pass out," she said and hung up the phone.
Police also contacted Voong's sister to say her brother was dead. She told police that Voong was attending language classes at the civic center. She said Voong is a U.S. citizen and has been in this country for 28 years.
Voong had recently been laid off from IBM in Johnson City, U.S. Rep. Maurice Hinchey, a Democrat whose district includes Binghamton, told the Associated Press. The gunman opened fire on a citizenship class, he said.
"People were there in the process of being tested for their citizenship," Hinchey said. "It was in the middle of a test. He just went in and opened fire."