How do you determine if a past participle--when used as a pre-modifier of a noun--is a verb or an adjective?
a. I saw a broken vase.
b. I saw a murdered man.
I think broken in a. is an adjective whereas murdered in b. is a verb. (Correct me if I'm wrong.)
Is there any clear way of determining the part of speech of a past participle pre-modifying a noun?