TL;DR - Audited by IRS but had 200 boxes of losing tickets & records in storage facilities, which the auditors apparently didn't want to search through. He ended up winning his defense against the state's tax claims as well.
How does he win so much? Is he psychic?
Edit: just read the article. Seems to be cashing in for others.
Covered his tracks by keeping thousands and thousands of non-winning tickets that he probably bought bulk for pennies per box.
Feds show up and see the boxes and say "shit, this guy must have really bought 300 million bucks worth of lottery tickets!" and walk away.
Pretty bad investigstion lol
There have been lots of groups that have made lots of money by intelligently playing specific MA lottery games at specific times, so those 300m tickets might be real.