After owning this artwork and labeled as "Artist Unidentified" for many years, and thanks to illustrator and Facebook friend Nick Runge, I have now discovered that this artwork was done by the brilliant Ralph McQuarrie, he of Star Wars fame!
Compare the art with the scans of the original poster comps as well as the comp for a billboard advertisement which were done under the original working title "Phantom", and the Theater Press Book as well!
This movie is a semi-documentary based on the real life string of mysterious killings that terrorized the people of Texarkana, Arkansas in 1946. The murder spree became known as the "Texarkana Moonlight Murders" and ultimately would claim five lives and injure many others, with the only description of the killer ever obtained being that of "a hooded man". To this day no one has been convicted and these murders remain unsolved. It's a tough to find film, but despite the low rating on IMDB, I saw it and despite the low budget, felt it was quite entertaining. It stars Ben Johnson and features Dawn Wells of Gilligan's Island fame!
Props to IMDB, and also to John Scoleri of Dreams and Visions Press, publishers of The Art of Ralph McQuarrie.
BOARD: 20 x 24 1/2
IMAGE: 14 1/2 x 21 5/16
Mixed Media on 1/8" Illustration Board