More details about Major League Baseball's investigation into the Houston Astros' alleged sign-stealing scandal have come to light. MLB is asking about the use of wearable devices to relay signs, according to ESPN's Jeff Passan. Also, MLB has requested access to phone records for some Astros executives.

Passan says MLB has already interviewed Astros manager A.J. Hinch, Red Sox manager Alex Cora and new Mets manager Carlos Beltran, as well as several players and front office members. Cora was Houston's bench coach in 2017. Beltran was a player on that team. Several people have been interviewed multiple times by MLB.

Here's more from Passan:

Players have been asked about "buzzing," via the use of Band-Aid-like wearable stickers; furtive earpieces; pitch-picking algorithms; and other potential methods of sign-stealing, the sources said. Accusations about the extent of the alleged wrongdoing have streamed into commissioner Rob Manfred's office from officials of other teams, the sources said. MLB officials are endeavoring to separate fact from fiction, the sources told ESPN, and the league has not concluded whether any such methods actually have been used.  

Kevin Goldstein, a special assistant to GM Jeff Luhnow, sent an email to Astros scouts instructing them to steal signs ahead of the 2017 postseason, even if it meant using cameras. MLB's investigation hopes to uncover the depth of the alleged sign-stealing scandal and exactly how far up the ladder it went. Manfred recently said the investigation is focused only on the Astros at this point.

Passan says players who cooperate with the investigation have been told they can expect leniency when it comes time to hand down discipline; however, front office personnel and members of the coaching staff could face stiff penalties. Several players who are no longer active have declined to be interviewed. MLB's rules require only active players to participate in an investigation.

Houston's alleged sign-stealing scheme came to light earlier this month when Mike Fiers, a member of the 2017 Astros rotation, blew the whistle. The Astros had a camera fixated on the catcher's signs, with the feed relayed to a monitor in the tunnel between the dugout and clubhouse. Someone would then bang a garbage can to relay the incoming pitch type to the hitter.

The Red Sox were fined for using Apple Watches as part of a sign-stealing scheme in 2017 and Manfred warned teams caught cheating in a similar way would be severely disciplined going forward. Earlier this year MLB issued a memo reminding teams that electronic sign-stealing carries a heavy penalty after Houston was caught videotaping opposing dugouts last postseason.

Manfred promised a "really thorough" investigation and there is no known timetable for discipline to be handed down. It would seem likely all parties hope to get this wrapped up before Opening Day.