Federal prosecutors have abandoned their attempts to reinstate several charges against Dr. Murdock Head, the former Airlie Foundation director convicted last year of engaging in a criminal conspiracy.

Head, 56, founder and longtime executive director of the Warrenton-base foundation, is currently appealing his conspiracy conviction. The prosecutor's move means that, if Head's conviction is overturned by an appellate court, he can be retired on only two of the 13 counts on which he was originally indicted.

Head was convicted by a U.S. District Court jury in Alexanderia last October of a single conspiracy court and was sentanced to three years' imprisonment by Judge Oren R. Lewis.

Head, who is free on a $5,000 personal recognizance bond, stepped aside as Airlie's executive director after the guilty verdict. He also relinguished his day-to-day duties as a professor and chairman of the George Washington University department of medical and public affairs.

Head was charged with conspiring to bribe former representative Daniel J. Flood (D-Pa.) and Otto E. Passman (D-La.). The Washington Post later reported, however, that the jury interpreted the conspiracy count narrowly and did not believe Head guilty of arranging to bribe either congressman.

Instead, The Post reported, the jurors found that Head had conspired to commit tax infractions, including arranging an improper $11,000 loan to a former Internal Revenue Service agent.

The prosecutors disclosed their decision to drop their efforts to reinstate eight other illegal gratuity and tax-falsification counts against Head in a brief filed late Monday with the 4th U.S. Circuit Court of Appeals in Richmond.

The brief constituted the government's initial response to Head's appeal. Head's lawyers have argued that his conviction should be overturned, in part, because Judge Lewis gave what they describe as improper instructions to the jury, particularly on complex issues dealing with the statute of limitations. The prosecutors replied in their brief that Lewis' jury instructions were not in error.

If Head's conviction is overturned, he could be retried on the conspiracy count along with one other bribery charge that had been set aside by Lewis. Head was acquitted of two other tax-evasion counts and Lewis dismissed a third tax-evasion count after the jury reported itself deadlocked.

Prosecutors previously had said they would appeal Lewis' dismissal of the eight other counts against Head. But in their brief, they said they would drop their appeal of these dismissals, partly because of complex "double jeopardy" issues.