The FBI is investigating allegations that officials in the St. Louis Cardinals’ front office illegally hacked into a computer database belonging to the Houston Astros, a federal law enforcement source told Fox News Tuesday.

The source could not elaborate further on the investigation, which was first reported by The New York Times.

The Times, citing law enforcement, reported that investigators uncovered evidence that officials from the Cardinals broke into the network that included information about players and personnel. The alleged hacking does not seem to be sophisticated, officials told the paper.

The paper said, if true, the attack would be the first reported case of a professional sports team hacking into another.

The Cardinals issued a statement saying the team is aware of the investigation and "has fully cooperated with the investigation and will continue to do so."

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"Given that this is an ongoing federal investigation, it is not appropriate for us to comment further," the statement read.

MLB said the Astros' "baseball operations database" was breached, but declined further comment until the federal investigation is completed. The U.S. attorney in St. Louis, Richard Callahan, says he is unaware of the investigation. Messages seeking comment from FBI officials in St. Louis, Houston and Washington were not returned.

"Major League Baseball has been aware of and has fully cooperated with the federal investigation into the illegal breach of the Houston Astros' baseball operations database," MLB said in a statement. "Once the investigative process has been completed by federal law enforcement officials, we will evaluate the next steps and will make decisions promptly."

Baseball Commissioner Rob Manfred said he couldn't recall a similar case in baseball's long history.

"Until we know, this is different than when we might investigate a drug case (or) we have access to all the facts in a real time situation," he said in Boston. "That's just not the case here. We don't exactly what the facts are."

MLB's forensics experts were not involved in the case, Manfred added.

"This is a federal investigation not a baseball investigation," he said. "Obviously any allegation like this, no matter how serious it turns out to be, is of great concern to us."

Law enforcement officials told The Times that they believe those behind the hacking were vengeful front-office employees that were targeting the work by Astros' general manager Jeff Luhnow, who worked with the Cardinals until 2011. Cardinals officials may be concerned that Luhnow took proprietary baseball information with him to the Astros, investigators told the paper.

It wasn't immediately clear how many Cardinals employees were under investigation, or whether top front office officials were possibly aware of the activities.

Luhnow was not made available to reporters in Houston on Tuesday, but he said in June 2014 that the team had been the victim of hackers who accessed servers and published months of internal trade talks on the Internet.

"It was an illegal activity and we're going to pursue it and try and find out who did it and prosecute," Luhnow said at the time, noting that the team was working with the FBI and Major League Baseball security to determine who was responsible for the breach.

The Astros rely heavily on sabermetrics in their evaluation of players and have been open about the fact that they use an online database to house their proprietary information. Last year, the Houston Chronicle had a detailed report on Ground Control, noting the team even had a director of decision sciences and that everything from statistics to contract information to scouting reports were stored at a web address protected by a password.

"One of the things I have been talking to my counterparts about with other clubs is recommending that everybody take a look at their own security systems and make sure they don't get hacked the way that we were," Luhnow said last year after the hack became public knowledge. "Because this definitely was an illegal activity."

Manfred downplayed wider security concerns about MLB's digital systems.

"We have a technology company that quite literally is the envy of companies throughout America — not just sports enterprises," the commissioner said. "We routinely make the resources of MLB Advanced Media available to all of the clubs. We have the type of security arrangements that are necessary."

The New York Post reported that the Cardinals and the Astros are currently in first place in their divisions.

The Cardinals have the best record in baseball (42-21)  and reached the National League Championship Series nine times since 2000, The Post reported.

The Cardinals are among baseball's most successful franchises on and off the field. Only the New York Yankees have won more World Series titles than the 11 won by St. Louis. They also are among the best-drawing teams in all of sports, with annual attendance topping 3 million every year since 2003. This season, the Cardinals have not had a crowd smaller than 40,000.

The Astros and Cardinals were rivals in the National League Central until Houston moved to the American League in 2012, but there is a prominent connection between the two: The Astros hired former Cardinals scouting and player development executive Jeff Luhnow as general manager in December 2011, and he has helped lead turn the team from a laughingstock that into a contender.

The Associated Press contributed to this report