Two retired New York Police Department detectives investigating the death of young men who have drowned in rivers, including the Mississippi River near La Crosse, believe a group of serial killers may be responsible.

In a story first reported by Minneapolis ABC affiliate Channel 5 Eyewitness News, and then featured on Good Morning America Monday morning, detectives Kevin Gannon and Anthony Duarte said the deaths of 40 athletic, intelligent and well-liked college students were linked by crime-scene clues. At the scene where some of the young men supposedly entered the water, a cryptic “smiley face” had been drawn.

The deaths have almost always been deemed the result of alcohol and drowning. However, the death of Chris Jenkins, in October 2002, has been deemed a homicide.

Gannon and Duarte say they've discovered a link between Jenkins' death and the drownings of at least 40 other men in 25 cities in 11 different states. The detectives don’t believe the killings are the work of a single individual, but rather a group.

According to the Channel 5 report, “City after city, when they'd find the spot where the body went in, they would find something else: The symbol of a smiley face. The paint color and size of the face varies, but the detectives are convinced that it's a sick signature the killers leave behind.”

The face has been in Wisconsin, Ohio, Pennsylvania, Indiana and Iowa.

In Michigan, they found something strange, graffiti including the word 'Sinsiniwa.' A few months later when they arrived in Dubuque, Iowa, to investigate a death of Matt Kruziki. His body was found on Sinsiniwa Avenue. Plus, they've discovered the nicknames of people in the group at more than one location.

Sinsiniwa Creek is a tributary of Fever river, in Illinois. It partially runs in Wisconsin. A nearby land feature, “The Sinsiniwa Mound” is named for it. The Sinsiniwa Mound is the home of the Sinsiniwa Dominicans Sisters, a Catholic order convent. Many religious and cultural events are held at Sinsiniwa Mound.

On Monday morning, the detectives said they were bringing the investigation to the public now to help people protect themselves, but that also they were running out of money to continue the investigation.

Channel 5’s investigation can be found online at: www.kstp.com