Nancy Grace

He never mentioned anybody else was there beside him and his three buddies, all dead, frozen dead in the backyard.

And he goes three days and doesn't notice they're on his back porch.

There's a mystery guy, a fifth person, Alexis.

To air exam joining me right now, Platts County prosecutor who is charged with lassoing all this evidence and presenting it to a jury.

Did he really think we wouldn't find out about the fifth guy, the mystery man?

And all of his statements at the get go, that was never mentioned.

Now we know why.

He was the dope dealer.

Crime Stories with Nancy Grace.

As we told you at the time, the victims had gathered at Willis' home January 7 to watch a Kansas City Chiefs playoff game against the L.A.

Chargers.

They never came home.

Two days after the men were last seen alive, one of the victims, McGinney's fiancée, forced her way into the home and found the three men dead in the backyard.

Now, prosecutors allege Willis provided the drug that killed all three, and cohort Carson supplied additional drugs in the weeks before.

Under Missouri law, any time a death occurs in the commission of a crime, whether intended or not, felony murder can be charged.

The temperature that night was just 18 degrees Fahrenheit.

One of the victims seated upright in a patio chair.

The others lying sprawled nearby, ice crusted on their faces.

Investigators now calling it, quote, foul play by stealth.

And toxicology reports confirm all three died of cocaine laced with fentanyl.