Or they don't want to be accused later of tunnel vision, incompetence, or missing something by the "Seconday Investigation" team.
My thoughts exactly. The family already has a good idea what the police investigation is going to show, and they have already hired one of the best lawyers in the province and a private investigator. Seem to me this may be a similar strategy to that of John Ramsey. The problem here is that if LE deems this a murder/suicide, there is no trial, no day in court. Barry Sherman will simply be deemed a murderer and that will be his legacy. The Ramsey's were very good at creating doubt, publicly releasing (mis)information to the public that pointed towards an intruder. I believe the Sherman family may do the same thing here, but time will tell.