Officers at the scene found the man face down, with his pockets turned inside out.
He was severely beaten on his head and had blood on his face.
Investigators believe he may have been robbed.
The man is described as a Hispanic male in his 30's, wearing a red short sleeve polo shirt, black jeans and black boots.
The man was determined to be 5' 7" tall, weighing 238 pounds.
The medical examiner found his cause of death to be blunt traumatic head injury.
Officers are trying to identify the man through fingerprints.
Anyone with information on this crime is asked to contact the Norwalk Police at 203-854-3111.
Anonymous Internet tips can be submitted via the anonymous tip link at the Norwalk Police website at: www.norwalkpd.com.