NEW YORK (CBSNewYork/AP) — Opening statements began Friday in the murder trial of a Queens man accused of gunning down an NYPD officer in 2015.

Hands cuffed behind his back, 37-year-old Demetrius Blackwell was led into court Friday, 1010 WINS’ Al Jones reported. Blackwell has pleaded not guilty to aggravated murder and other charges in the death of Detective Brian Moore.

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Moore’s family was also at the courthouse, along with dozens of police officers, in a show of strength and support.

The defense attorney told the jury to keep an open mind and consider the fact that Blackwell has a case of epilepsy so severe that medications won’t work and he had brain surgery that could have changed his mental state, WCBS 880’s Alex Silverman reported.

Assistant District Attorney Daniel Sanders said that is not a reason to kill.

“It’s the typical playbook for the defense to say, ‘Look, my guy has issues. He has an excuse why he pulled the trigger,” Lynch said. “But I don’t know about you, I have family and friends that have epilepsy, and they don’t kill New York City police officers.”

Lynch sat in the courtroom listening to the prosecutor describe how, after his arrest, Blackwell claimed to have had a seizure, but a paramedic determined he had not.

The prosecutor’s account was straightforward, saying Blackwell shot Moore because he didn’t want to be caught with an illegal gun.

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The 25-year-old officer and his partner were in street clothes in an unmarked car when they attempted to stop Blackwell, who was suspected of carrying a handgun. Authorities say Blackwell opened fire, striking Moore in the head. He died two days later.

Moore’s partner and others picked out Blackwell from a lineup, and prosecutors said Blackwell’s DNA was found on the two bullets left in the cylinder.

Moore was posthumously promoted to Detective First-Grade. He’d been on the job for five years. In that time, he made 150 arrests and was awarded two medals for his duty. He followed in his father, uncle and cousin’s footsteps.

His mother has been advocating for stricter sentencing after learning her son’s alleged killer has a long rap sheet.

Blackwell is a convicted felon with nine previous arrests on his record, including attempted grand larceny, assault, robbery and weapons possession, CBS2’s Magdalena Doris reported.

Blackwell is also facing attempted murder for allegedly firing at Moore’s partner, Erik Jensen.

If convicted, Blackwell faces up to life in prison without parole.

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