Authorities confirmed the break-in to reporters on Tuesday morning, per CBS Boston. Officers were called to the property shortly after the Pats returned to Foxborough, Massachusetts, on Monday.
Blair White of Boston 25 had earlier tweeted the following report on a possible burglary:
According to ESPN.com, state and local police were at Gronkowski's home throughout Monday night, just a few miles away from Gillette Stadium.
Foxborough Police Chief William Baker confirmed that items were stolen from Gronk's home: "There were items stolen. We're not going to release the nature of the items stolen. Obviously the people who committed the theft know what was stolen. It's an investigative advantage for us to know that as well and not share it with the public, so I won't have any further comment on that."
Gronkowski and the Patriots fell 41-33 to the Philadelphia Eagles in Sunday's Super Bowl, marking the fifth Super Bowl loss in franchise history.
The 28-year-old Gronk enjoyed a strong individual performance in defeat, catching nine passes for 116 yards and two touchdowns.
After the game, Gronkowski told reporters he would "look at [his] future" during the offseason when asked about potentially retiring, according to ESPN.com's Mike Reiss.
Gronkowski was cleared to play in the Super Bowl after suffering a concussion that knocked him out of the AFC Championship Game against the Jacksonville Jaguars.