For the young Bronx police officers on their way to help patrol a major demonstration in Midtown Manhattan, the early morning assignment on Sunday was a reprieve from the daily danger of a violent precinct.

But as the police van in which they were riding rounded a notoriously sharp turn on the Bruckner Expressway just after 5 a.m., the driver lost control and the van slammed into a barrier, ejecting a 25-year-old rookie officer onto the rain-slicked roadway.

The officer, Michael Williams, was pronounced dead less than an hour later at Lincoln Hospital. Eight other officers who were in the marked police van, a 2009 Ford Econoline, were hurt, though their injuries were not life-threatening, the police said.

Image Officer Michael Williams. Credit... The New York City Police Department

Mayor Bill de Blasio called the crash a tragedy and said he was “heartsick” at the death of Officer Williams. “The notion that this was a guy just starting out, who loved what he was doing as a police officer and had a whole bright future ahead, and he lost it in this tragic accident,” the mayor said, speaking to reporters at the climate change protest that some of the officers in the van had been assigned to patrol.