A law officer who recently appeared before the special grand jury reviewing how Alexandria Public Safety Director Charles T. Strobel conducted a 1984 drug investigation said that his home in Prince William County was threatened by an anonymous caller the night before he testified.

Louis Pugh, a former Alexandria officer who is now a deputy sheriff in Prince William County, said that the night before he testified his wife received a telephone call from a man who did not identify himself and said "he hoped we had a lot of fire insurance on our house."

Pugh said he reported the call to the Prince William police. A police spokesman confirmed the report had been received.

The officer, who appeared before the grand jury Feb. 7, also said that John W. Turner, the Alexandria policeman serving subpoenas for the panel, twice initiated a discussion with him about a matter on which Pugh later testified.

Turner, who works as an investigator in the city commonwealth's attorney's office, said he did not recall discussing the testimony with Pugh. "Maybe I did," he said.

Asked whether it was proper for a person serving subpoenas to discuss potential testimony with a witness, Fairfax County Commonwealth's Attorney Robert F. Horan, who is special counsel for the grand jury, said: "I don't know . . . . I don't know how Turner would know what a witness is going to say."

Strobel made his second appearance yesterday before the special grand jury, which is in its fourth week of hearing testimony. Also appearing yesterday were City Council member Donald C. Casey, former police detective Charles Cox and Alicia Mundy, a reporter for The Port Packet, which first reported allegations that Strobel prematurely halted a drug investigation that had partially focused on suspected drug use by Alexandria Sheriff Michael E. Norris.

Pugh said he told the special grand jury Feb. 7 that Strobel ordered him to stop "investigating information that was supplied to me by a confidential informant . . . that two police officers from another jurisdiction may have had knowledge of or possibly something to do with" a 1971 homicide in Arlington.

Pugh said Strobel, then a captain and head of the police department's inspectional services section, did not give him any reason for halting his investigation. A lawyer for Strobel declined comment on Pugh's allegations.

Pugh said that Turner brought up the subject of the 1971 Arlington homicide during a telephone call the night before Pugh testified. Turner had called Pugh to tell him the panel wanted to hear from him the next day.

The deputy sheriff said the next day he and Turner had a brief conversation about the 1971 murder of a man named Hugh H. Howard when he went to Alexandria to pick up his grand jury subpoena. Pugh said that Turner then told him that the murder had been solved.

Pugh said that was the first time he heard the case had been solved and "I testified in there on the assumption that it was solved."

Asked about this, Turner said that he and Pugh "discussed several different things" on the telephone that night and that the homicide "could have come up." But he said he didn't "know what Louis Pugh's testimony was going to be."

"I have heard it was solved," Turner said but declined to say who told him that.

Arlington Police Department spokesman Thomas Bell said, however, the slaying is unsolved and still an open case.

Circuit Court Judge Donald H. Kent, who impaneled the special grand jury Jan. 15, declined comment on Pugh's statement.

In a separate action yesterday, lawyers for two Alexandria policemen and a former police detective who filed suit Jan. 30 in federal court in Alexandria against the City of Alexandria, Strobel and police Lt. John Stedman, alleging the officers had violated their civil rights, dropped their claims against Stedman.