April 28, 2008 -- Chris Jenkins was a popular student at the University of Minnesota who disappeared one night in 2003.
Four months later, he was found dead in the Mississippi River. At first police thought Jenkins was just a drunk college kid who accidentally fell into the river and drowned after a night on the town.
But for two retired New York City Police detectives, Jenkins' death became the link that connected the drowning deaths of 40 young men — usually high-achieving college students — in 25 cities in 11 different states.
Detectives Kevin Gannon and Anthony Duarte have been tracking the suspicious drowning deaths of young men across the country ever since they investigated the death of college student Patrick McNeill, who drowned in New York City in 1997. Gannon made a promise to McNeill's parents that he would never give up on his case.
When the detectives took a look at Jenkins' death, they discovered that the position of his body and other physical evidence proved that the college student didn't drown accidentally. The cause of death on Jenkins' death certificate was changed to "homicide."
In city after city, the detectives found a smiley face painted somewhere at the crime scene. The color of paint used and the size of the faces varies, but the detectives are convinced it is a sick signature claiming responsibility for the homicide.
The detectives found the smiley faces in Ohio, Pennsylvania, Indiana, Wisconsin and Iowa.
Gannon and Duarte also came to the surprising conclusion that more than one person is involved in the murders.
"Because there's such a wide range of states the killings are through," Gannon said today in an exclusive interview on "Good Morning America." "Besides the fact that we have multiple victims on the same night."
At the crime scene of a drowning in Michigan, Gannon and Duarte discovered grafitti that they believed was written by the killers, but were puzzled by a word they hadn't seen before.
"We found 'sinsiniwa,' which was very suspicious at the time," said Gannon.
Then the detectives found the strange word in Iowa, where they were investigating the drowning death of 24-year-old Matt Kruziki.
Bloodhounds tracked Kruziki's scent to an intersection near the Mississippi River. The detectives believe that is the location where the killers slid Kruziki's body in the water — it was at Sinsiniwa Avenue.
"We believe they were specifically leaving a clue for us or anyone who was paying attention to these drownings, that the cases were ultimately linked," Gannon said.
Paul McCabe of the FBI office in Minneapolis said the bureau investigated some of the deaths late last year and concluded that they were accidental drownings. He said an FBI behavioral analysis, requested by a Wisconsin police chief, concluded that there was probably not a serial killer at work.
McCabe said his office is not actively investigating any of the deaths but would be interested in seeing any new information that Gannon and Duarte had discovered.
Gannon said they were publicizing their conclusions now because they are looking for help.
"Right now really we're out of finances and really can't do any more on the cases. In fact, we looked at 89 cases in totality. We knocked out 30 right away and there was 19 cases that we haven't even done yet and out of those 19, they look like at least 10, 15 of those could be connected," Gannon said.
Chris Jenkins' mother, Jan, like the McNeills and other families, want answers about how their son died.