Police in St. Lucia say an autopsy determined that a British man recently attacked on his yacht died from asphyxia as a result of being beaten.

Authorities said Tuesday that three suspects are in custody and will be charged at a later date. They did not specify when.

The killing of 62-year-old Roger Pratt late Friday surprised many people and raised questions about safety on the island in the eastern Caribbean. His wife, Margaret, also was beaten and was treated at a hospital for cuts and bruises.

She said in an interview released Tuesday that no knives or guns were used in the attack.

The Warwickshire couple had been traveling aboard their yacht, the Magnetic Attraction, since June to celebrate her 60th birthday.