Pennsylvania racing officials are investigating whether a veterinarian used a handgun to euthanize a horse at a track near Philadelphia, a possible violation of track rules and racing industry standards.

Dr. Thomas J. Lurito is banned from Philadelphia Park pending the outcome of several reviews of the June 10 incident, Pennsylvania Racing Commission spokesman Chris Ryder said Friday.

Racehorses are typically put down with an overdose of barbiturates, and guns are often prohibited in and around tracks, experts said. Philadelphia Park bans guns unless someone has permission from the state racing commission to carry one, Ryder said.

"Frankly, I'm a little taken aback. It's just not the way it's done," said veterinarian Rick Arthur, the equine medical director to the California Horse Racing Board.

The death was first reported by the Daily Racing Form, which said the horse was a 4-year-old filly named Rich and Mean. It was not clear why the horse was being put down.

Lurito, a Philadelphia Park employee, has been licensed with the racing commission since 1995. He did not return messages left by The Associated Press at several listed numbers.

The racing commission, track officials and Bensalem police are investigating aspects of the reported shooting, which involved a .22-caliber handgun, Ryder said.

Gunshots can be a humane way to put down animals, but the practice is no longer done at U.S. racetracks, Arthur said.

Messages left with a Philadelphia Park spokesman and Bensalem police were not immediately returned.