The New York City Police Department is stepping up security at Sikh temples around the city after Sunday’s deadly shooting at a Wisconsin temple, according to an article from NY1 News.

More details are being released by authorities about the suspected shooter, as law enforcement sources identify him at 40-year-old Wade Michael Page, who served in the U.S. Army for about six years.

While the FBI reports that the investigation is still in its early stages, the Bureau has stated that the attack is being viewed as an act of domestic terrorism, the article says.

Investigators say that the gunman opened fire Sunday morning at a temple in the Milwaukee suburb of Oak Creek, killing six worshippers. An officer who was helping a victim was also shot, the article reports.

A second officer shot and killed the suspect.

The officer who was shot and two other people wounded in the attack are now in critical condition, the article reports.

In response to the shooting, the NYPD has increased its presence around Sikh temples around the five boroughs.

According to the Sikh Cultural Society, there are nearly 10,000 Sikhs living in New York City, the article says.

The 500-year-old religion, originating in India, preaches equality and peace.