A Fairfax County police officer has been dismissed and another is under investigation following complaints that the two were involved in "indiscretions" with two Explorer Scouts on a ski trip to Pennsylvania, police officials said yesterday.

Police Chief Carroll D. Buracker said the officer was dismissed after an internal investigation prompted by complaints to the department. He said the investigation involving the second officer is still pending. The chief declined to identify either officer.

The "indiscretions"--which police would neither describe nor characterize yesterday--allegedly occurred on a two-day ski trip in Pennsylvania in late February in which the two officers and four married couples accompanied members of the police-sponsored Law Enforcement Explorer Scouts, Buracker said. The county police support two such units, one based in McLean and the other in West Springfield; both have male and female members, aged 14 to 21.

Buracker said the two Explorer Scouts involved in the incident have been dismissed from the Explorer program. He said the four married couples serving as chaperons on the trip reportedly knew nothing about the alleged involvement between the Scouts and the police officers.

The two officers were off duty at the time of the ski trip, which was not sanctioned by the police department, Buracker said.

Rudolph Flythe, head of the scouting National Capital Area Council, said last night he had not been informed of the incident. Flythe then spoke with a Fairfax police captain and said the captain assured him that the incident did not occur on an official Explorer trip.

"He did say to me that to his knowledge, whatever it was, they were not acting as Explorers at that time," Flythe said.

The police-sponsored Explorer posts in Northern Virginia recently came under fire from National Boy Scouts of America for their use of scouts as decoys in police efforts to crack down on a beer sales to minors. The national organization has a policy against using scouts in such activities.

Brian Archimbaud, national director of the Law Enforcement Explorers program, said last night he knew of no incidents like the latest one in Fairfax.

"The potential is there whenever you have men and women working together," said Archimbaud. "It's just a tragedy when these things happen." Archimbaud said that "from all I've heard, the post there has a very high-caliber program. I hope this won't affect it.