Video of Man Cuffed in Underwear Amid Chiefs Fans' Mysterious Deaths

Video of a man being handcuffed in his underwear as police discovered three dead bodies in his backyard is finally surfacing -- the latest development in this wild case out of Missouri.

You've probably heard of this by now -- it all has to do with this guy named Jordan Willis in Kansas City, who was hosting a Chiefs watch party at his house back in early January with some friends ... only for 3 of them to turn up as stiff corpses on his property days later.

The story is absolutely insane ... and it's still shrouded in mystery. Here's what cops know for sure though -- at some point after the watch party on Jan. 7, families for 3 of the attendees at Willis' get-together (David Harrington, Ricky Johnson, and Clayton McGeeney) reported them missing ... as no one had seen or heard from these men after that evening.

People had attempted to contact Willis himself, of course, but he too was off the radar for a couple days -- that is, until officers arrived at his home on Jan. 9 ... where he reportedly answered the door with a wineglass in hand ... and wearing nothing but tighty-whities.

That's exactly what you're seeing in this new video here, which just popped up courtesy of NewsNation reporter Alex Caprariello, who says he obtained it through his reporting.

In the brief clip ... you can see a neighbor recording the police run-in Willis experienced that night -- capturing all the officers who responded to the scene ... and them detaining Willis.

And yes, he indeed in his underwear ... just as reports have indicated from the get-go.

It's worth noting, while Willis might've landed in handcuffs here in the moment -- after which officers discovered the bodies of Harrington, Johnson and McGeeney, frozen to death in Willis' backyard -- he did NOT get arrested or charged with a crime ... and hasn't as of yet.

Police there are saying no foul play is suspected thus far in the investigation -- and they're even going out of their way to say this is not being looked into as a homicide ... despite some troubling details that have the public doing double takes and scratching their heads.

Willis, for his part, has denied any knowledge about how his friends turned up dead in his backyard ... and says he wasn't even aware anyone was looking for them. He's denied having anything to do with their demise ... this despite the families' collective outrage.