A black veteran Ohio sheriff's deputy filed a civil lawsuit against a white security guard for allegedly pointing a gun at him during an incident in May at an Internal Revenue Service office in Toledo.

Alan Gaston was in full uniform when he stopped by the IRS office for personal reasons on May 31, according to a lawsuit filed in the Lucas County Common Pleas Court. Gaston has worked for the county sheriff's office for the past 35 years, his lawyer Chad Tuschman said.

Seth Eklund, a security guard at the office, stopped Gaston and told him he needed to remove his gun, the suit states. Gaston asked if there was a locker for him to store it and was told that there was not one. Eklund then told Gaston to put his gun in his car.

Gaston refused and "attempted to discuss the matter" with Eklund, according to the lawsuit, but Eklund "unholstered his gun and pointed it directly at" Gaston. Eklund then grabbed Gaston's shoulder, telling him he was being detained.

Eklund was charged with aggravated menacing, according to NBC affiliate WCMH-TV in Columbus, Ohio. He pleaded not guilty in his first court appearance on Monday.

Tuschman said in a statement that Eklund's not guilty plea did not come as a surprise.

"He clearly remains unrepentant," he said on behalf of Gaston. "This security officer was poorly trained, he was undoubtedly not qualified for the position he held."

"If you couple those facts with racist thoughts and/or feelings, you end up with this result. Apparently a fully uniformed black deputy is not safe when it comes to racial hostility," he added.

The incident was caught on camera and shows Gaston walk into a room and appear to talk to someone off camera. As Gaston leaves the room, Eklund is seen walking behind him with his gun pointed at Gaston's back.

Gaston said in an interview that he thought Eklund was going to shoot him.

"There's really no way to know how you're going to act when there's a gun pointed at you and you think you're going to lose your life," he said.

The suit states that Gaston suffered "severe emotional and psychological distress and has suffered extreme personal trauma." He and his wife, Michelle Gaston, are seeking damages in excess of $25,000.

The other two defendants named in the lawsuit, security companies Paragon Systems and Praetorian Shield, could not immediately be reached for comment.