A Massachusetts judge has issued her ruling in the trial of a man charged with causing the 2016 death a state police trooper on the turnpike.

David Njuguna, 33, of Webster, was found guilty of involuntary manslaughter, misdemeanor motor vehicle homicide by reckless operation, negligent operation of a motor vehicle and operating an uninsured motor vehicle.

In Judge Janet Kenton-Walker's ruling Tuesday afternoon in Worcester Superior Court, Njuguna was found not guilty of OUI manslaughter and felony motor vehicle homicide with drugs and negligence.

Prosecutors had said Njuguna was speeding and high on marijuana on March 16, 2016, when he struck Trooper Thomas Clardy's stopped cruiser on the Massachusetts Turnpike in Charlton.

"Mr. Njuguna recklessly crossed three lanes of traffic at 80 miles per hour, all the way into the breakdown lane and at 80 miles per hour crashed into the back of the cruiser," Kenton-Walker said.

She said even though Njuguna was reckless, his demeanor was inconsistent with the appearance or demeanor of someone high on marijuana, as explained by experts who testified during the trial.

"There was no evidence that the level of THC found in Mr. Njuguna's blood meant that his ability to operate his motor vehicle was impaired," Kenton-Walker said.

The judge added that the science behind marijuana impairment is not yet established.

"I find that at the present time, there is no consensus within the medical or scientific community regarding the meaning of the level of THC found in blood when determining impairment," Kenton-Walker said.

Njuguna's previous lawyers said he had some sort of medical issue that caused a seizure and made him lose control of his vehicle. His new defense attorney said he plans to appeal the verdict.

Testimony in the case wrapped up Oct. 29.

Following the verdict, State Police Colonel Kerry Gilpin reacted saying in part, "There always will be an empty seat at the Clardy's table, and a hole in the hearts of the Massachusetts State Police. This verdict cannot bring Trooper Clardy back to his family, friends, and colleagues, but it does provide some sense of justice by holding the defendant accountable for his actions that day."

Njuguna's bail was revoked and sentencing is scheduled for Nov. 21. He could face up to 20 years in prison for the involuntary manslaughter charge.