After months of praising Saudi Arabia’s cooperation in the investigation of the bombing last June in Dhahran that killed 19 American airmen, the Clinton administration’s top law enforcement officials abruptly changed tactics on Thursday, assailing the refusal of Riyadh to share information.

Attorney General Janet Reno said that the Saudis had failed to turn over “very important information” from the investigation. Her comments followed those of FBI Director Louis Freeh, who was quoted on Thursday complaining that the Saudis had provided “hearsay” information that made it impossible to fully evaluate the evidence.