foul play

But Davis said: "Can I say we're going to rule out foul play? We can't answer that. That might be days or weeks or months before we can do that."

An investigation into his death found no evidence of foul play.

Although two investigations - one carried out by Germany's aviation accidents agency and another by a Malawi government-appointed commission - did not find evidence of foul play, some Malawians remain suspicious of the authorities.

On Monday, it said it had found "no foul play" in the zoo's management.

On May 25, her Chevy Avalanche was located off Highway 36, and evidence recovered at the scene suggested to investigators that the mother of four had been the victim of foul play, Johnson said.