A MARYLAND STATE POLICE investigation has confirmed disturbing reports about the conduct of a small group of Prince George's County police oficers in the late 1960s. According to a report released Friday on the advice of state Attorney General Stephen H. Sachs, police "planned or assisted in the planning" of store robberies that led to the deaths of two suspects. The investigators cited evidence that county police officers staked out the stores after using informants to recruit the suspects to perform the robberies. But the report concluded that the officers who participated in the stakeouts did not commit homicide in either case, since they had no knowledge of the details of their assignments.

That is an ugly chapter in the history of the county police. But release of this official report is important not only to all concerned citizens who had read the allegations, but also to the majority of diligent county police officers, who were not involved in any way in these incidents.

County Executive Lawrence J. Hogan, while noting the number of years that have passed since the incidents, went too far in belittling the findings. Ever since a briefing on the report earlier this month, Mr. Hogan has been saying that "some of the investigative techniques employed by the police department 12 years ago . . . would not be tolerated in our police department today. However, the conduct of our officers should be judged against the 1967 standards, not the standards of 1979."

However dim recollections of 1967 may be, the conduct described in the report was no more acceptable then than it is now. As the county official now engaged in choosing the next police chief -- after months of searching -- Mr. Hogan should have the distinction straight. To shrug off this kind of conduct as something curiously medieval is to invite public uneasiness about exactly where standards are today. Thanks to Mr. Sachs, the public is able to put the incidents in better perspective.