Murder in the Library

In the third book in the Lt. Dekker/Sgt. Murdock series, a man is found dead inside the locked library of his home. Surveillance cameras show that no one other than the deceased entered the library, and yet the man has been shot with a poisoned dart. The case means even more to the two detectives than any of their previous cases, because the deceased was a mentor to both of them when they were boys. The deceased had received a threatening note, which the two detectives knew about, and he ha...