Twenty-five Irvington police patrolmen were recently promoted to the rank of supervisor, marking the single largest promotion in the town’s history, officials said.

The police division’s 167-member rank now boasts 40 sergeants, after about 15 percent of the force was sworn-in earlier this month to their new positions.

“Promotions are always big boosters of morale,” Mayor Tony Vauss told NJ Advance Media. “Prior to me getting here, some people get promoted and others don’t, we want to promote everybody. This was our opportunity to promote a little more.”

Irvington has seen a dramatic decrease in crime over the last few years. Once averaging 25 to 30 homicides a year, there were five murders last year -- an 81 percent drop from 2003. The township has recorded two homicides in 2019 so far.

“Everything hinges on leadership. You can have a contingency of troops but if you have no leadership telling them where to go, it loses effect,” Public Safety Director Tracy Bowers said. “Leadership and training, that’s what caused us to have the success we’ve had lately.”

Vauss said recent retirements of some top cops left large leadership vacancies that needed to be filled. He doesn’t expect the sergeant salaries -- that start at $118,000 -- to be a “major expense.”

“For two years I haven’t replaced the deputy chiefs and more retirements are coming this year and next year,” Vauss said. “It’s money that we were going to spend anyway.”

Bowers said some of the newly-promoted sergeants remain in their old assignments but now have supervisory responsibilities.

“It’s the same amount of people on the street,” he said.

Robberies, aggravated assaults and burglaries are also at the lowest levels ever recorded, officials said. For the last three summers, the township has had no homicides, Vauss said. He credits that to increased community policing and having officers patrol neighborhoods on bicycles during the warmer months.

A promotion ceremony for the new sergeants is planned for July, Vauss said.

Karen Yi may be reached at kyi@njadvancemedia.com. Follow her on Twitter at @karen_yi or on Facebook.

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