The difficulty of figuring out if Harley Lawrence died before a Berwick, N.S., bus shelter caught fire or after could be the reason police haven’t said how he died, a former chief medical examiner says.

Lawrence died eight days ago. Police called the death suspicious the day the homeless man died, but haven’t said anything new since.

It’s not known if his death was an accident or deliberate, or if the fire took his life or started after he died.

John Butt was Nova Scotia's chief medical examiner during the huge forensic investigation that followed the crash of Swissair 111.

He said Thursday that the first step in the Lawrence investigation would be to examine the site of the fire.

“For example, where the fire might have started, what direction the fire moved, and indication of accelerants,” he said.

Lab tests can take time

Butt said blood tests can usually determine if a victim was alive when a fire started. In rare cases involving fires in confined spaces, establishing the cause of death can be more complicated.

“If this is the case — and let's make sure that we understand that nobody said that that is one of these cases — but if that is the case, these things require a significant amount of deliberation,” he said.

Butt said a medical examiner will sometimes call on independent experts to consult on fire deaths.

He believes the medical examiner may be waiting on results of laboratory tests.

“I suspect in this case, the matter here has to do with the toxicology and potentially the use of an accelerant,” he said.

Strategic reasons

Butt also raised the possibility that autopsy results are being held back by police for strategic reasons in a criminal investigation.

Officials would only repeat what they've said for the past week.

“There's not really much more we can say. The medical examiner is still doing his work. But it's still under investigation, and then part of an RCMP investigation as well,” said Chad Lucas, spokesman for the Justice Department.