A civilian Fairfax County police employe yesterday sued the county, its police department and two senior police officials in federal court, claiming he was unfairly disciplined for providing a copy of an internal 1980 inquiry critical of the department to The Washington Post.

The employe, Robert E. Jurgensen, maintained in the suit that he was threatened with dismissal, but later was allowed to sign a "voluntary request" for demotion and transfer dictated by Major Kelly Coffelt, the official in charge of the department's Emergency Operations Center.

Fairfax police spokesman Warren Carmichael said yesterday department policy prohibits commenting on pending litigation.

The internal report, detailed in a June 26, 1981, Post article, said morale and staffing problems in the county's emergency communications center--the facility that handles police, fire and rescue calls--were so severe that "its ability to function effectively is in question." The report had not been officially released to the public.

In his suit, filed in U.S. District Court in Alexandria, Jurgensen claimed he was demoted "in retaliation for his having engaged in 'whistle-blowing' beneficial to the public but embarrassing to defendants."

Shortly after the article was published, the suit said, Jurgensen acknowledged to police internal affairs officials that he had supplied a copy of the report to The Post. He later met with Coffelt and Chief Carroll D. Buracker, who were named yesterday as individual defendants, and signed the voluntary demotion request under duress, he said.

According to the suit, Jurgensen later asked Buracker to rescind the request and instead allow the case to be handled under routine personnel regulations. Buracker refused, the suit said.

The suit asks for a total of $250,000 in damages, claiming violation of Jurgensen's rights of free speech, due process and his rights as an employe under state and county law.