Jiverly Wong was upset over losing his job at a vacuum plant, didn’t like people picking on him for his limited English and once angrily told a co-worker, ‘America sucks.’

It remains unclear exactly why the Vietnamese immigrant strapped on a bulletproof vest, barged in on a citizenship class and killed 13 people and himself, but the police chief says he knows one thing for sure: ‘He must have been a coward.’

Jiverly Wong had apparently been preparing for a gun battle with police but changed course and decided to turn the gun on himself when he heard sirens approaching, Chief Joseph Zikuski said Saturday.

‘He had a lot of ammunition on him, so thank God before more lives were lost, he decided to do that,’ the chief said.

Police and Wong’s acquaintances portrayed him as an angry, troubled 41-year-old man who struggled with drugs and job loss and perhaps blamed his adopted country for his troubles. His rampage ‘was not a surprise’ to those who knew him, Zikuski said.

‘He felt degraded because people were apparently making fun of his poor English speaking,’ the chief said.

Wong, who used the alias Jiverly Voong, believed people close to him were making fun of him for his poor English language skills, the chief said.

Until last month, he had been taking classes at the American Civic Association, which teaches English to immigrants and helps them prepare for citizenship tests.

Then, on Friday, he parked his car against the back door of the association, burst through the front doors and shot two receptionists, killing one, before moving on to a classroom where he claimed 12 more victims, police said.

The police chief said that most of the dead had multiple gunshot wounds. Wong used two handguns – a 9 mm and a .45-caliber – for which he had obtained a permit more than a decade ago.

The receptionist who survived, 61-year-old Shirley DeLucia, played dead, then called 911 despite her injuries and stayed on the line while the gunman remained in the building.

‘She’s a hero in her own right,’ he said.

Police initially said it took 90 minutes to rescue her. On Saturday, Zikuski said it was actually 39 minutes, and he said the police response followed all proper procedures.

‘The police did the right thing,’ he said.

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