While I don’t think there was, or is, any kind of conspiracy related to the actual death of Justice Scalia, I do believe he should have been autopsied. In most states, he would have had to have an autopsy by law, due to the circumstances of his death.
There are medical autopsies (to find out what happened medically), and medico/legal autopsies (required by law). Justice Scalia's death actually meets compelling reasons for both, IMO.
In most states, a person who dies unwitnessed, unexpected, without an obvious cause (such as trauma, motor vehicle accident, etc), and who is also not under the DIRECT care of a physician (such as in a hospital, hospice care, or long term care facility), is subject to a medicolegal requirement for autopsy, independent of the wishes of the family.
It is a very unusual peculiarity of Texas law that the justice of the peace who pronounced Justice Scalia dead over the phone, is allowed to independently decide to require, or NOT require, an autopsy, sight unseen. Purely because this man was a prominent SCOTUS Justice, whose death was unwitnessed, unexpected, during an out of state trip, and with no obvious cause of death beyond “his heart stopped”, I believe strongly he should have been autopsied.
Now we will have “conspiracy theories” for a very long time, from those who will perpetuate the idea that his death may have been caused, or the circumstances manipulated (avoiding autopsy, death in a remote location, dismissed federal marshalls protection, pronounced dead over the phone, etc), to achieve political means. That’s never good, IMO. The JOP made a very bad call avoiding autopsy in this situation, IMO. No one, absolutely NO ONE would have criticized the JOP for REQUIRING an autopsy under these circumstances, but many will strongly condemn the decision to avoid one.
Ask yourself-- if the POTUS of any political party persuasion, went on vacation, and died under similar circumstances, would there be an autopsy? Of course there would. To rule out foul play, and conclusively establish cause of death.