1) brought up cases of amateurish killer and unsung
= reverse the outside letters of AmateurisH KilleR UnsunG
= AH KR UG backwards
= GURKHA - a soldier from Nepal in the Himalayas i.e. highland warrior
2) with = W, men = O.R., busy investigating = D.S.*, a boy = A LAD
*busy is slang for policeman e.g. a Detective Sergeant
and word salad is a "jumble of incoherent speech as sometimes heard in schizophrenia"
http://www.thefreedictionary.com/WORD+SALAD
3) recalled = put backwards...
ultimately falsE = E, claim by actor = I DO, of = OF
= E I DO OF reversed
= FOODIE - a course (i.e. food) lover