Contact the police in the jurisdiction and relay your concerns in regards to the suspicious manner of death. Law enforcement will then investigate the case and determine if they think a postmortem exam is appropriate. If the police agency finds this is necessary, they will petition the court to order an exhumation and autopsy. In other words, the exhumation and autopsy must be court ordered. You mentioned that the husband does not want this to occur. He has absolutely no say in the matter and his wishes are not relevant in a criminal investigation.