NEWS ACCOUNTS THIS WEEK by staff writers John Feinstein and Eugene L. Meyer have brought to light some disturbing allegations about the conduct of a small group of Prince George's County police officers in 1967. One allegation is that this group, which came to be known as the "Death Squad," used a contact to arrange an armed robbery during which a man was killed by the police. A former detective from this group and a police informant who worked with it each told The Washington Post virtually the same story about a June 1967 robbery. That robbery and two others in the same year ended in police shootings -- including one other fatality. According to the detective and others involved, the police actions resulting in the deaths were designed as a deterrent to would-be robbers at a time when there had been a rash of holdups in the county.

The informant, Gregory Gibson, has told reporters that he was ordered by Joseph D. Vasco, now a lieutenant colonel and second in command of the police department for the last three years, to arrange the June 1967 robbery. Mr. Vasco has denied any role in arranging the robbery. The store was staked out by police, and during the robbery, 18-year-old William H. Mathews Jr. was killed by the police. Five weeks after that death, Mr. Gibson narrowly missed being shot to death by then-Det. Vasco -- during an attempted store burglary. In all, county police conducted three stakeouts in 1967, according to the accounts, which resulted in three shootings and two fatalities.

Based on inquiries by the reporters, County Executive Lawrence J. Hogan and Police Chief John W. Rhoads ordered their own investigation, in which a county attorney, who is the departmental legal adviser, found no criminal wrongdoing by police. But this week, Mr. Hogan said he asked the Justice Department and the FBI to investigate the allegations, nothing that a separate investigation by neutral outsiders would "clear the air once and for all." According to Mr. Hogan, however, Justice and FBI officials both said that too much time may have elapsed to prosecute possible crimes committed in 1967. Mr. Hogan says that, if Justice declines to investigate, he will probably ask "some other disinterested third party, possibly the state police," to do so, nothing that "the story raised some legitimate questions that should be resolved."

Mr. Hogan is right to pursue the matter. Without prejudging the allegations in any way, the accounts have raised suspicions and tensions in the county that demand more than an internal investigation.It is noteworthy that the Fraternal Order of Police, the union of the officers, has voted to "stay in the middle until all the facts are in," according to its president, Laney Hester. Perhaps an investigation should be conducted jointly by the state attorney general and the office of the special prosecutor. But the county government owes it not only to all concerned citizens but to the majority of diligent police officers who were not involved in any way to review the accounts as thoroughly as possible.