IT COULD take 18 months before the cause of a plane crash which killed three leading lights in the Furness business world is fully known.

Colony Candles founders Alan Williams, his estranged wife Sue Williams and her sister Gill Williams were all killed alongside Mr Williams's new partner, Deborah Winn, when their plane came down in remote jungle in Tanzania's Mahale National Park.

Last month the Tanzanian Civil Aviation Authority said engine failure was the most likely cause of the holiday plane crash which also claimed the life of its Canadian pilot.

But authority officials and the Cessna plane's manufacturers still have to look at the charred wreckage to try to determine exactly what went wrong.

A Foreign Office spokesman said: "The Tanzanian authorities are still investigating it. They have done an interim report and they are speculating that it's engine failure. It could take a year to 18 months before we get a final answer as to what has caused it."

Last week the badly burned bodies of the Furness group were flown to Manchester Airport from Dar es Salaam and have been taken to Westmorland General Hospital.

A specialist team from Cumbria Police that has been working on identifying victims of the Asian tsunami and London bombings will now formally identify the bodies using a range of techniques.

"Tests will have to be sent off so it's likely that process will be complete early in the New Year," said police spokesman Mike Head.

"There will then be a coroner's inquest to confirm the identity and funeral arrangements will be made after the bodies are released."