A Philadelphia police officer has been arrested and charged with striking his fiancee's 18-year-old son with his service gun and pointing the weapon at him, authorities said yesterday.

Police said Marcus Dingle, 37, a 10-year veteran, was charged with aggravated assault, recklessly endangering another person, and related offenses. Dingle, assigned to the Fifth Police District in the WissahickonCQ section of the city, was suspended for 30 days with intent to dismiss.

Police were called to the home Dingle shared with his fiancee in the 6400 block of North 11th Street about 1:45 a.m. Wednesday. Investigators determined that Dingle had struck the young man in the back of the head with the gun during a confrontation and pointed the weapon at him while making threats. Dingle, who left before police arrived, was arrested at the Internal Affairs Bureau, police said. He was released after posting $5,000 bail.

Dingle could not be reached for comment yesterday. A spokesman for the the Fraternal Order of Police declined to comment on the case. - Vernon Clark