CHICAGO (CBS) — An admitted drug dealer has been sentenced to life in prison for killing a plainclothes Chicago police officer who was attempting to execute a search warrant at the defendant’s home four years ago.

Lamar Cooper, 40, was convicted of first-degree murder in January for the shooting death of Officer Nathaniel Taylor, a 14-year police veteran.

Judge Nicholas Ford sentenced Cooper to the mandatory natural life sentence at a hearing on Tuesday.

Taylor, 39, was gunned down while assisting with the execution of a search warrant on Sept. 28, 2008.

nathaniel taylor 0123 Drug Dealer Gets Life In Prison For Killing Chicago Cop

Chicago Police Officer Nathaniel Taylor (Credit: Chicago Police Department)

Cooper was accused of killing Taylor when a team of drug officers tried to serve Cooper with a search warrant.

Police later recovered drugs, cash, guns and other weapons from Cooper’s home, where he allegedly was running a home delivery drug business.

In closing arguments of the trial in January, the defense acknowledged Cooper was a drug dealer and that he shot Taylor, but argued Cooper could only see a vague shape approaching his car and could not see Taylor’s police shield hanging on a chain around his neck, so Cooper thought he was being robbed and fired in self-defense.

But prosecutors ridiculed the defense’s claim, calling the shooting a “sneak attack” on Taylor, saying drug dealers know how police operate and know narcotics officers often wear street clothes instead of their uniforms.

Prosecutors said, even if Cooper couldn’t see Taylor’s police shield and thought he was being robbed, he could have fled, called 911 or fired a warning shot into the air.

Taylor’s partner, Lem Miller, fought back tears as he testified at the start of the trial about seeing Taylor get shot in the head, chest and arm as he walked up to Cooper’s car.

Taylor and Miller were assigned to conduct surveillance on Cooper’s home on the morning of Sept. 28, 2008, in preparation for a team of officers to serve a search warrant on the home at 7 a.m.

When Cooper pulled up in front of his house around 5:30 a.m., Taylor and Miller were told to detain Cooper to keep him from entering his home, as police believed there were weapons, dogs and children inside.

Miller testified that, as Taylor approached Cooper’s car, Taylor identified himself as a police officer. The next thing his partner heard was two or three rapid shots. Then he saw Taylor go down.

Miller said he drew his gun and fired at Cooper 10 times, hitting him nine times before calling for help on his radio and checking on Taylor.

Taylor, 39, died hours later during surgery at Advocate Christ Medical Center in Oak Lawn.

Cooper had already done time for attempted murder of another police officer in 1990. Prosecutors said, in that case, Cooper shot at uniformed police officers. He was sentenced to 6 years in prison for that case. He also has two burglary convictions on his record.

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