Problems May Hurt Prosecution in Marine Case, White House Says

President Reagan has received a briefing from national security advisers about problems that have developed in the Marine sex-and-spying cases, according to White House spokesman Marlin Fitzwater, who said Monday: “These cases may be difficult to prosecute.”

“The President certainly is concerned about the quality of the investigation and the case in the sense that we want to prosecute whoever has been involved in espionage activities,” Fitzwater said.

He added: “I don’t want to signal guilt or innocence in advance, but if there has been espionage by the Marines or anyone else associated with these embassies, we want to prosecute, and we want the cases to be as sound as they can be.”

Fitzwater declined to discuss the problems in the cases, but internal military documents have indicated that the Marine Corps investigation has been hampered by a lack of cooperation from the State Department, the CIA and the National Security Agency.

In addition, the Washington Post reported Monday that a lack of evidence, retractions of statements by key witnesses and faulty interrogation of suspects have also been damaging.

Three former Marine guards who have served as sentries at the U.S. Embassy in Moscow and the U.S. Consulate in Leningrad have been accused of assisting Soviet intelligence activities after accepting sexual favors from Soviet citizens.