The latest museum heist hit an unlikely target: the Yogi Berra Museum and Learning Center, on the Montclair State University campus in Little Falls, New Jersey. During the break-in, which occurred Tuesday night, several objects belonging to the Hall of Fame baseball player were stolen.

According to the Daily News, sources describe the thieves as “a team of professionals” who had targeted specific pieces of valuable memorabilia prior to the break-in. The burglars accessed the museum through adjoining Yogi Berra Stadium, where the New Jersey Jackals play.

A college spokesperson declined to release a list of stolen objects, explaining that “it is still in the early stages of the investigation.”

Berra won 13 World Series titles during his career, including 10 as a player. The museum collection includes 10 of his championship rings, 2 of his MVP awards, numerous baseball cards, and the jacket Berra wore at Game One of the 2009 World Series, where he threw out the first pitch. The museum, which opened in 1998, also exhibits broken baseball bats from mid-century stars of the sport such as Gil Hodges, Willie Mays, and Stan Musial.

“The Yogi Berra Museum and Learning Center is an iconic asset to our county and to parents, children, and baseball fans everywhere,” said Essex County sheriff Armando Fontoura in a press conference. “We are outraged that this vital institution was violated.

Dave Kaplan, the museum’s director, says that state and federal authorities are pooling their resources to solve the crime, with a $5,000 cash reward being offered by Essex County police for tips that help authorities make an arrest in the case.

Some fear that the stolen materials will be difficult to track down, given how difficult it would be to move such items outside of the black market.

“This is very unique material and it would have to stay underground,” Rob Lifson, a sports memorabilia expert and the president of Robert Edwards Auctions told the Daily News. “These are not mass-produced items—it’s like trying to sell a famous painting. Anyone who bought them would have to keep it secret. Why not just steal the Mona Lisa and try to sell that instead?”