The first of the dead have been identified from Pan Am Flight 103, and investigators began tests Tuesday on a suitcase for clues as to whether a bomb or structural failure caused Britain's worst air disaster.

Police said they hoped to release five or six bodies to next of kin Tuesday once the last formality of registering the death in Lockerbie was completed. Names and nationalities were not issued.One more victim was found Monday, bringing the total in two temporary morgues in the city hall and an ice rink to 240.

Pan Am said it has determined that another infant was on board Flight 103, bringing the total of passengers and crew on the plane to 259. Eleven townspeople are still listed as missing and feared dead.

After three days of constant rain, more than 600 rescue workers resumed their search under clear skies Tuesday for the remaining victims and for missing wreckage, including sections of the airplane's wings.

Police divers joined the rescue effort, searching the icy, rain-swollen waters of the lakes, reservoirs and bogs in the 100 square miles of rugged terrain and dense woods surrounding the crash zone.

Civilian and Royal Air Force pathologists and a group of orthodontists examined bodies in temporary morgues in the town hall and ice rink, but expected the identification process would take another 10 days.

Police spokesman Angus Kennedy said Tuesday that three more men had been arrested after being found in possession of parts of the aircraft.

The men, ages 20, 21 and 40, will appear in court on Wednesday, along with a 28-year-old man who was arrested Monday for looting at the crash.

"I am disgusted with certain things I have seen - at the very thought that something like this could happen in the midst of all this, when everyone else is trying to help," said Paul Newall, the area's chief deputy constable.

A suspect suitcase and an unspecified amount of wreckage were sent Monday to the Royal Armament Research and Development Establishment in southern England "for more detailed examination to determine whether they exhibit evidence of a pre-impact explosion," Michael Charles, the top British investigator on the scene, said in a statement.

Transport Department press officer Penny Russell-Smith said the tests began Tuesday and might be concluded "as early as tonight or perhaps a few days."

The Times of London reported that the suitcase, noticed lying among wreckage, was ripped and torn and might have been damaged by flying metal. The report said the Fort Halstead scientists "should quickly be able to establish whether those marks were made by an exploding bomb."

Charles' statement added that although no evidence of structural failure had turned up, that was still being probed as a possible cause.

Structural failure or a bomb have been identified by experts as the most likely reasons why the Pan Am plane disappeared from radar screens just as it reached cruising altitude of 31,000 feet over southwest Scotland on Dec. 21.