SALISBURY (CBS) — A woman and her boyfriend are facing assault charges, accused of punching a lifeguard in the face.

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It was a steamy Sunday on Salisbury Beach and the shoreline was packed with people.

That’s when the lifeguard saw some swimmers out too far and blew his whistle.

Police say it was too much for 42-year-old Shawn Duncan of Lawrence.

Shawn Duncan (Photo courtesy: Salisbury Police)

Shawn Duncan (Photo courtesy: Salisbury Police)

He ordered the lifeguard to stop the whistle blowing because it was “aggravating his hangover,” police said.

The lifeguard told them he was just doing his job.

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That’s when witnesses and police say Duncan and his girlfriend, 24-year-old Erin Mulcahy, attacked the lifeguard; dumping a bucket of water on his head, punching him in the face and knocking him to the ground.

Erin Mulcahy. (Photo courtesy: Salisbury Police)

Erin Mulcahy. (Photo courtesy: Salisbury Police)

“I believe the female party struck the lifeguard knocking him down. The male party was also summonsed because of the assault and he had some issues here where he threatened the lifeguard back at the station,” Chief Thomas Fowler said.

Witnesses say a huge crowd gathered around the lifeguard and the suspects, including 6’5″ Duncan, but nobody tried to stop the assault.

Both suspects have been ordered to stay away from the lifeguard and Salisbury Beach.

The police chief says alcohol does seem to be at the root of this case.

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The lifeguard is not believed to have been seriously hurt.