Angry relatives of victims of Pan Am Flight 103 called for a congressional probe into the deaths of 259 people aboard the plane and 11 others when a terrorist bomb blew a Boeing 747 apart over Scotland in December. Neither the government nor the airline has answered questions about the Dec. 21 crash, particularly why passengers were not warned of threats the airline received before the flight, victims’ relatives said at a meeting in New York with Scottish police officials. The meeting was called to discuss plans for the return of personal effects from the crash site. “We have a political action committee that is working on getting Congress to do a full investigation . . . " said Paul Hudson, head of Victims of Pan Am Flight 103, an organization of relatives of people who died in the crash.