A Billerica Police sergeant was killed while working at a road construction site on Friday, authorities say.

Middlesex DA Marian Ryan and Billerica Chief of Police Roy Frost said that Sgt. Ian Taylor, 59, was killed while working at a construction site on Billerica’s Boston Road.

“We’re all very emotional. It’s been a long day,” Chief Frost said during a press conference at the scene while surrounded by officers from his department. “Every single one of the officers that work with Ian love him like a brother.”

They said in a statement that an excavator was backing up on the site when it struck Taylor shortly before 2 p.m. He was transported to Lahey Hospital where he later died.

Taylor, who spent 21 years in law enforcement, was “an unbelievable police officer,” Frost said, adding that he joined the department in 2011.

Taylor’s death struck a chord with police departments across the commonwealth.

“We are devastated to hear of the passing of @BillericaPD Sgt. Ian Taylor,” the Wilmington Police Department, where Taylor worked from 2010 to 2011, tweeted.

The Tewksbury PD released the statement, “All of us here … are deeply saddened by the tragic passing of Billerica Police Sgt. Ian Taylor. We extend our heartfelt condolences to Sgt. Taylor’s family, friends, and the Billerica Police Department and community.”

The incident is under investigation by local and state police and is also under an investigation by the Occupational Safety and Health Administration (OSHA), authorities say.