Season four, ep. 16. Aired Feb. 16, 1984. Eugene Roche returns as hardboiled gumshoe Luther H. Gillis. Sheree North. Geoffrey Lewis as the hot dog guy.
https://www.imdb.com/title/tt0639748/
http://magnum-mania.com/Episodes/Season4/The_Return_of_Luther_Gillis.html
