Which can be addressed if the people feel that way. Constitutionally.
Sorry if the system isn't set up as you would like, call your representative or senator. Start a constitutional admendment drive if you like, but it is the way it is.
On the question of whether any criminal can call as witnesses people who are alleged to be involved but whom cannot be found and whether that would necessitate a finding of not guilty; I find that question to be inane. Call a lawyer for the technical answer.