Dozens of officers aided by a helicopter and an air-boat combed through marsh 30 miles east of here yesterday for two men who abducted a teen-age couple from a park and shot them, killing the young woman and severely wounding her companion.

Patrolman Gus Krinke said the two men, armed with a 16-gauge shotgun and believed to be fugitives from a New York State bank robbery, apparently shot their victims "just to keep them quiet."

A statement issued by the sheriff's office said it was possible that the men, described as in their mid-20s and dressed in olive drab clothing, already had stolen another car and escaped.

John Chantrey, 16, was in critical condition after being shot in the stomach and hip and left for dead.

The body of his companion, Rachelle Rees, 18, was found 300 feet away. Her car was found abandoned nearby.

Krinke said the two men were seen shooting at a Mercedes on a tree-lined boulevard near the park Sunday. Police believe the men were firing at their own car. A check of license plates on the abandoned Mercedes showed it was reported stolen and wanted in connection with a bank robbery in Mount Vernon, N.Y.