After the spying allegations first emerged, Bielsa, 63, admitted in a television interview before kick-off against Derby on 11 January he was responsible for the member of staff found acting suspiciously outside the Rams' training ground.
Leeds United manager Marcelo Bielsa has come out fighting against accusations of "cheating" and "unethical" behaviour in a controversial spying incident that has been a talking point in British football for the past week.
Bielsa called an impromptu press conference on Wednesday, sparking rumours he could sensationally resign as he has in shock fashion at Lazio and Marseille in the past.
The EFL had already confirmed both it and the Football Association were investigating the matter, but have now confirmed the involvement of Leeds' rivals in the investigation.
"In a few words I can tell you we observed all the rivals we played against and we watched all the training sessions of the opponents before we played against them".
He said: "What I've done is not illegal".
"As Lampard says, he doesn't believe I have bad intentions".
In the aftermath of that match, the English Football League has asked Bielsa and Leeds to explain the "spygate" scandal, while Derby boss Frank Lampard remained highly critical of the incident.
His coaching style has also proved to be an inspiration for the likes of Atletico Madrid coach Diego Simeone, Pochettino and Manchester City manager Pep Guardiola, who has described Bielsa as the best coach on the planet.
"Many people have condemned the behaviour saying it was immoral and affecting fair play, saying that it was cheating, many managers and ex-players thought my behaviour was disrespectful".
"My desire is to help put the club in its real place in the Premier League", Casilla said.
"For the guys in charge of the big clubs it's easier than the other ones".
"We can discuss it, it's not seen as a good thing but it's not a violation of the law". You change a lot of things, you train on the set-pieces, you use the players who are available for the weekend.
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