LONDON (AP) — British officials are investigating the unexplained death of a Russian businessman, a key witness against Russian officials who allegedly stole $230 million from a London hedge fund in a money laundering scheme.

Alexander Perepilichny’s body was discovered Nov. 10 outside his rented house south of London. Police said a second post-mortem on the 44-year-old former milk factory owner would begin Friday after a previous one had proven inconclusive. It could still take months to get the new toxicology results, Surrey Police spokeswoman Nicola Burress said.