Leeds United head coach Marcelo Bielsa has admitted he sent one of his staff to Derby County's training ground ahead of Friday's Championship clash.
Frank Lampard's pre-match preparations for the Elland Road fixture were disrupted on Thursday morning after a man was caught acting suspicious outside the club's training facility.
The Rams released a statement on Friday morning claiming it was a member of the Whites footballing staff and now the Argentine has confirmed it was his decision to send one of his personnel to Derby's training ground.
“It’s true there was someone from Leeds United, the responsibility of this is me, I am responsible, there is some precision that I need to give," Bielsa told Sky Sports ahead of the clash.
"It doesn’t matter if this is legal, illegal, right or wrong, for me it’s enough that Frank Lampard and he told me I didn’t respect fair play.
"I have a different point of view on it but the important thing is what frank and Derby think. I am responsible for it because I didn’t ask for Leeds United permission to do it. Without trying to find a justification I have been using this kind of practice since the qualifications for the World Cup with Argentina.
"This is not illegal, we have been doing it publicly, we talk about it in the press, for some people it is the wrong things for others it’s not."
Frank Lampard also gave his verdict on the incident, saying: "I spoke to him yesterday afternoon. He did the same [admitted the incident] to me so I am pleased he's done it again. I think it makes it easier to deal with.
"At least on a sportsman's level it's bad in my opinion. If we're going to start talking about culturally 'I did it somewhere else' then that doesn't work for me because I don't believe it is fine.
"It has disrupted our build-up to this game. People are going to say I am standing here trying to make an excuse but I'll speak like this after the game and more if I have to."
Derbyshire Police confirmed no arrests had been made after they attended a call to the Rams training ground at 11:20am on Thursday.