The man killed by police after shooting three of his colleagues at a Middleton technology company last week was not legally able to own firearms, police say.
The 43-year-old man, identified as Anthony Tong, had moved to Madison from South Dakota in March of 2017 and began working at technology company WTS Paradigm in Middleton a month later.
Police in Sioux Falls, South Dakota revoked Tong’s concealed carry permit in 2004 after authorities became concerned with the state of his mental health.
An affidavit from the Minnehaha County Sheriff’s Department in Sioux Falls described Tong as in possession of multiple guns and a large amount of ammunition. He reportedly claimed “there were people at work that were talking bad about him.” As a result, his weapons and ammo were confiscated and he was barred from purchasing any more.
Police say the gun used in the shooting had not been purchased legally and its origins are being investigated by the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Other than the 2004 incident, Tong did not have a criminal record.
The medical examiner confirmed Tong was killed by police gunfire and did not commit suicide, Middleton Police Chief Charles Foulke said in a press conference Friday.
Middleton police identified the officers who fired their weapons during the incident as Richard O’Connor and Tyler Loether. Deputies David Lambrecht and Matthew Earll from the Dane County Sheriff’s Office also fired at Tong. Until the investigation is completed, all four have been placed on paid administrative leave.
Law enforcement raided Tong’s house Thursday morning after attaining a search warrant. According to the warrant, he had collected large amounts of weapon parts and ammunition in his house.
Police have not yet determined a motive for the shooting, but Foulke said the raid on the house produced “significant evidence.”
“We must use caution in trying to jump to conclusions that this is a mental health-related shooting incident,” Foulke said. “We need to be cautious that we don't paint everyone with the broad brush of everyone with a mental health issue is going to become an active shooter.”