LOS ANGELES (AP) _ A memorandum outlining the U.S. government's strategy for prosecuting four police officers on charges they violated Rodney King's civil rights was leaked to the defense, National Public Radio reported.

NPR, citing sources it didn't identify, said the memo, known as an ''order of proof,'' was received by attorney Michael Stone, who represents Officer Laurence Powell.

NPR's report was to be broadcast on its ''Morning Edition'' newscast Friday.

The memo apparently listed what government prosecutors hope to prove in the case, what evidence they plan to use, witnesses they intend to call and witness testimony. The memo also reportedly discusses weaknesses in the government's case and how prosecutors will deal with them.

''This casts such a shadow over the integrity of the Justice Department that I simply cannot discuss it,'' said Assistant Attorney General for Civil Rights John Dunne, who is in charge of the prosecution.

Powell, Sgt. Stacey Koon, and Officers Theodore Briseno and Timothy Wind face trial in February on charges they violated King's civil rights. The officers were acquitted of most state charges in the March 3, 1991, beating of King following a car chase.

The April 29 acquittals sparked three days of rioting in Los Angeles in which 53 people were killed.

The state court jury deadlocked on one assault charge against Powell.

Attorneys for the four officers refused to comment on the reported leak and suggested they were barred by court order from speaking on the matter, NPR said.

''I can't even tell you whether I've been gagged,'' said attorney Harland Braun, who represents Briseno.

''It would be irresponsible for me to speculate on something like that,'' said King's attorney, Milton Grimes.

The sources told NPR that an investigation into the leak was under way by the Office of Public Integrity, which looks into criminal law violations.

A legal expert called the leak an unprecedented breach of security.

''It's incredibly rare that in a high or any kind of profile case that the government would itself leak to the defense its own strategy,'' said Abbey Lowell, a former Justice Department official.

Lowell suggested that it was possible some Justice Department officials may sympathize with the police officers.