Over the last two decades, hundreds of college-aged young men have reportedly been found dead in bodies of water from New York to Minnesota. Nearly all of the cases have been classified as accidental or undetermined drownings, yet there's a theory that at least 40 of these victims have been killed by an organized underground gang referred to as the “Smiley Face Killers” -- named for the chilling graffiti found near many of the bodies.

TELL DR. PHIL YOUR STORY: Have a story in the news?

A team of retired NYPD detectives and a professor of criminal justice say they don’t believe these athletic, smart young men just fell in a river and drowned, and they are investigating the deaths. They – and the mothers of six of the victims -- say they believe the men were abducted, killed and thrown in the river.

WATCH: Why Six Mothers Say They’re Convinced Their Sons Were Murdered And Did Not Die Accidentally As Classified

As part of their investigation, they did an experiment where they placed five pig carcasses into a pond to see the effects that water would have on the bodies of the victims if they were submerged for a period of time. In the video above from Wednesday’s episode of Dr. Phil, they reveal the results of their experiment – and why they say it proves that the bodies were dumped in the water after they were killed; they didn’t die in the water.

On Wednesday, hear more about the investigation. And, hear from the six mothers and why they say they are convinced their sons were murdered. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Have a story Dr. Phil won't believe?

Today’s Takeaway: Grieving Can Take Different Paths