Surveillance cameras from both the Loudoun County jail and the cruiser of Loudoun sheriff's Deputy John W. Gregory captured the deputy slamming a handcuffed prisoner to the floor after an arrest in June 2015. Gregory was convicted of misdemeanor assault, but appealed and was acquitted. (Loudoun County Sheriff's Office)

A former Loudoun County sheriff’s deputy who was convicted of misdemeanor assault after he threw a handcuffed man to the ground inside the Loudoun jail last year appealed his conviction and was found not guilty by a Loudoun Circuit Court jury Wednesday.

Surveillance videos from inside the jail’s receiving area showed then-Deputy John W. Gregory arriving with prisoner Lyle Grenoble, who was charged with being drunk in public. An in-car video showed that Grenoble was not hostile or resistant throughout a long arrest and transportation process, but that within seconds of arriving at the jail, he was body-slammed by Gregory, who loudly cursed Grenoble and ground his knee into Grenoble’s back, other videos showed.

Grenoble was sent to the jail’s infirmary and then later to a hospital for his injuries, though he was not seriously hurt.

Gregory Former Loudoun County sheriff’s deputy John W. Gregory, initially convicted of assaulting a prisoner, was found not guilty on appeal. (Caleb Kershner)

Gregory, 33, and a deputy for 10 years, was prosecuted in Loudoun General District Court, where retired Clarke County District Court judge Norman deVere Morrison found him guilty in November 2015, and fined him $500. Loudoun Sheriff Mike Chapman fired Gregory two weeks after that. Gregory appealed to the circuit court, where he was able to present expert testimony and persuade a seven-person jury to find him not guilty after about 90 minutes, his attorney, Caleb Kershner, said Thursday.

“The only real jury instruction we gave,” Kershner said, “was a self-defense instruction. It’s pretty evident that’s what they based their verdict on.”

Kershner said after Gregory was fired by the sheriff, he appealed through the county’s civil process and won. But he could not get his job back and is not working in law enforcement, Kershner said. A spokesman for the sheriff’s office said Thursday that the sheriff could not comment on personnel matters.

Kershner said Gregory testified in circuit court that Grenoble “exhibited numerous threatening gestures, that he felt the arrestee push into him, and that he saw an ‘I’m going to kill you’ look on the arrestee’s face.” He said Gregory, having worked for years in the Loudoun jail, recognized a threat to his personal safety and took him to the ground in “a controlled takedown maneuver.” A veteran police instructor testified that Gregory’s use of force was reasonable, Kershner said.

Grenoble’s attorney, Jerry Phillips, did not attend the trial but said that he was surprised by the verdict. He said that Grenoble told him “the officer didn’t have any reasonable grounds for attacking him. He can’t understand why it happened.”

Phillips added, “Like in the O.J. Simpson case, he was acquitted, but it doesn’t mean he is not liable for civil rights violations.”

He said Grenoble would be suing Gregory, though no case has been filed yet.

“This is a victory for our deputies who work our streets and protect us in the face of danger each and every day,” Kershner said. “Second-guessing our law enforcement except for excessive misconduct only handcuffs their ability to protect and defend us in the community. John was well-trained and acted according to his police academy training.”