A bottlenose dolphin calf, part of a small inshore pod living in the waters off the southwest coast of England, was discovered floating in the water after a number of boats were seen motoring around the pod, which had been swimming close to the coast, The Guardian reported Monday.
"It is believed several boats were in the area at the time and one of the dolphins was hit by a boat and killed," a spokesman for the Devon and Cornwall police said.
The British Divers Marine Life Rescue and the Cornwall Wildlife Trust issued a joint statement accusing some of the vessels of "harassing" the dolphins, a crime under British law.
Police were asking anyone who witnessed the incident or took photos or video footage of it to contact them.
Conservations called the incident a tragedy.
"This is a rare, small, inshore pod, a sub-species of the offshore bottlenose dolphins," Abby Crosby of the Cornwall Wildlife Trust said. "They are very intelligent and will mourn the loss of the calf."