Authorities on the Caribbean island of St Vincent say a British tourist found dead last week near his sunken boat had injuries consistent with an explosion.
Police say 53-year-old John Garner was the only person aboard the catamaran when it caught fire and sank on Friday.
Officials say Mr Garner's girlfriend is no longer being sought for questioning, adding that she had left the island a couple days before the apparent explosion.
Sailing experts have said it is not uncommon for people to die from propane stove explosions.
Police made the announcement after releasing the results of the post-mortem.