ROBERT RAYMOND CLARK was executed in Florida's electric chair Monday for the 1977 slaying of a businessman who was forced to write a $5,000 check at gunpoint, then shot to death . . . A FREIGHT TRAIN plowed into a car at a rural crossing near Fromberg, Mont., Sunday, killing all four people in the automobile. The motorist drove onto the tracks from a dirt road and apparently did not see the train, said Highway Patrol Officer Lance Bourquin . . . A LARGE ELEPHANT went berserk and plunged into a crowded market in Bangkok, Thailand, destroying property and injuring at least 10 people, a police official said Monday.