NEW YORK (AP) — A 16-year-old boy accused of setting a mattress fire that led to the death of a veteran police officer was indicted on a murder charge on Friday.

Marcell Dockery faces up to 25 years to life in prison if convicted in the death of officer Dennis Guerra, Brooklyn prosecutors said. The teenager had already been arraigned on assault, arson and reckless-endangerment charges and was being held without bail.

Guerra and his partner, Rosa Rodriguez, were overcome by smoke soon after reaching the 13th floor of a Coney Island public housing building last Sunday. Police said Dockery set fire to a mattress there out of boredom.

In a statement, Brooklyn District Attorney Kenneth Thompson called the fire a “senseless act.”

“We will bring the defendant to justice for these terrible and horrific crimes,” he said.

Dockery’s attorney Jesse Young, speaking to reporters after a brief procedural hearing in the case, called Guerra’s death “a tragedy” but said a jury would determine his client’s culpability, the Daily News reported.

The head of the city’s largest police union, Patrick Lynch, said in a statement he was pleased with the second-degree murder charge and hoped it would “start us on the road to achieving justice in this case.”

Guerra, 38, died Wednesday at a hospital in the Bronx. He had more than seven years with the New York Police Department and was the son of a police detective. He left behind a wife and four children, ages 7 to 20, police said.

Rodriguez, 36, remains in critical but stable condition at a Manhattan hospital.

Guerra’s death was the first of an NYPD officer in the line of duty since 2011, when an officer was shot and killed responding to a robbery in Brooklyn, police said. His funeral is scheduled for Monday.