Apparently the winner shared his lineup with his brother it appears.. The individual who won is the brother of a MM contest from last season.. Heres an excerpt from the article detailing the apparent hijinks and collusion

"The Millionaire is the most high-profile recurring contest for DraftKings. There were almost 257,000 entries in this week’s contest, at $20 apiece, creating a prize pool of $4,444,444 and a first prize of $1 million. Participants in the contest picked lineups of National Football League players and the teams that accumulated the most points based on real-world results won prizes.

Soon after the contest ended, posts on industry message boards and on social media focused on how one of the winners, with the username “papagates,” is a brother of another top player who last year won a previous Millionaire contest. Many of the posts alleged that analysis of the lineups submitted by the brothers—which DraftKings makes publicly available—indicated that they shared information to avoid any overlap.

If they did so, that would effectively allow them to circumvent the site’s rules that limit the number of entries per person and that also prohibit collusion among users.

Aguiar of DraftKings said the site’s user guidelines, which were released in August to clarify any confusion about the rules, expressly prohibit close cooperation among players."

The winner claims innocence but a review of both brothers lineups is very suspect indeed according to the analysis.

Draftkings claims their system flagged the issue before the story blew up but one has to ask a big question here.. Why wasn't the redflag triggered BEFORE the contest if they are trying to root out collusion and not afterwards?? Seems their algorithm is a little slow to pick up on stuff it should be catching before the problem occurs.. This isn't like poker where collusion is usually only caught during or after the hands play out.. These lineups are submitted prior to NFL kickoffs