The Houston Astros' illegal sign-stealing techniques began with an electronic system named "Codebreaker," according to a letter from commissioner Rob Manfred sent to then-Astros general manager Jeff Luhnow in January that Jared Diamond of the Wall Street Journal obtained.
An intern's PowerPoint presentation first introduced "Codebreaker" to Luhnow, and it was operated through the use of Microsoft Excel spreadsheets, Diamond reports.
The Astros had someone watching a live feed during the game, and they would log the catcher's signs and the pitch that was thrown into Excel. The system then decoded that information to determine what signs corresponded with what pitch. The information would then be passed on to Astros baserunners, who would relay the signals to hitters, according to Diamond.
At least one member of the organization referred to "Codebreaker" as "dark arts." Tom Koch-Weser, the Astros' director of advance information, referenced both "the system" and "our dark arts, sign-stealing department" in two emails sent to Luhnow during the 2017 season. Koch-Weser also said that he and Luhnow discussed the system during the 2016-17 offseason.
Koch-Weser told investigators Luhnow would also enter the team's video room during road games, Diamond reports, and casually ask, "You guys Codebreaking?"
Astros players took the system to the next level in June 2017, using a video monitor and banging on a trash can to relay signals. The Astros won the World Series that season.
While Diamond reports the trash-can banging stopped after 2017, Houston continued using "Codebreaker" to steal signs in 2018. The Astros used the system during both home and road games.
The Astros fired Luhnow hours after MLB suspended him one year for his role in the sign-stealing scheme. He denied being involved, saying in a statement last month he's "not a cheater" and was unaware of what his players and coaches were doing. Luhnow told investigators he saw Koch-Weser's emails discussing the system but didn't read all the way to the end, according to Diamond.
However, Manfred wrote in his letter that there's enough evidence to show Luhnow knew about the team's conduct.
The former GM also denied Koch-Weser's account of what happened, according to Diamond. Luhnow didn't respond to the Journal for comment on Friday.
Then-Astros manager AJ Hinch was also suspended for one year and, like Luhnow, summarily fired following the release of the investigation's findings. Hinch apologized for his role in the scandal earlier this week.
Alex Cora, who was Hinch's bench coach in 2017, and Carlos Beltran, a player on that club, also lost their managing jobs with the Boston Red Sox and New York Mets, respectively, in the fallout.
A separate investigation into whether Cora's Red Sox illegally stole signs in 2018 is ongoing, and it could conclude next week.