The FBI is investigating the St Louis Cardinals on charges that the US baseball team hacked into the computers of a rival club to steal player data, the New York Times has reported.
The alleged cyber-attack against the Houston Astros is thought to be the first time a professional sports team has been hacked by another.
Trade discussions and proprietary statistics were reportedly targeted.
Major League Baseball has confirmed the investigation.
Baseballs officials told the Washington Post that the breach is being taken seriously in the sport, which is known for its data-heavy approach to managing players and schedules.
