BOSTON (CBS) — Major League Baseball is investigating the Boston Red Sox for possible “circumvention” of MLB’s international signing rules with “package deals” made in the past year. Players as young as 16 were interviewed as part of the process and were reportedly “threatened” with suspensions if they failed to be truthful. The commissioner’s office denied that any such threats took place.

According to a report by Ben Badler of Baseball America, multiple sources say that MLB is focusing on the Red Sox’s signings of multiple Latin American players, mostly in Venezuela, during the 2015-16 signing period. Since 2012, the “bonus pool” has existed for all 30 major league teams to sign young players in countries like Venezuela and the Dominican Republic.

The Red Sox are being investigated for signing groups of players to “package deals,” which are multiple signings from the same program grouped together. The team reportedly exceeded its bonus pool budget in 2015 and as a result was not allowed to sign any players for more than $300,000. Though they reportedly did ink many players for that amount, they still landed two of the top 30 international players available at the time, who were presumably worth much more, which ostensibly raised some eyebrows in MLB offices.

There are no apparent rule violations in what the Red Sox did – Badler himself is dubious of MLB’s reasoning for conducting a formal investigation into the matter and supposedly intimidating the teenage prospects into giving them information. “Package deals” are not explicitly against MLB rules and no team has ever been penalized for such a signing, but the Red Sox are reportedly the only team under investigation.

Badler referred to his own April 25 story on how teams can side-step bonus pool rules by creatively allocating money between multiple players in package deals. MLB could be looking to determine exactly how the Red Sox made their signings and use the information to close loopholes and impose stricter restrictions or penalties on teams that they may believe are circumventing the rules already in place.