Pochettino was given a two-match touchline ban and £10,000 fine for his post-match row with Dean following Tottenham’s 2-1 loss to Burnley on February 23.
Pochettino accepted the improper conduct charge, with the FA now releasing the written reasons behind their decision to sanction the Spurs manager.
The relevant part of Dean’s referee report said: “At the conclusion of the game I was approached on the field of play by the Tottenham Hotspur head coach Mauricio Pochettino and some members of his coaching staff including first-team coach Jesus Perez.
“Mr Pochettino acted in a very irresponsible and aggressive (sic) manner. He wouldn’t stop saying ‘you know what you are, you know what you are’. I asked him to explain and he repeated ‘you know what you are’.
“I then said on numerous occasions to go away at least 10 times and he wouldn’t get out of my personal (sic) space and then aggressively (sic) pointed his finger just a few inches from my face again saying “you know what you are”. Mr. Pochettino then left me alone and left the field of play.
“When I reached the tunnel he was waiting at the top of the stairs again saying “you know what you are” and had to be escorted to the dressing room by security staff from Burnley.”
Both of the assistant referees at Turf Moor for the game corroborated the account of Dean.
Pochettino acknowledged the inappropriateness of his behaviour in his post-match interviews and apologised to Dean in his subsequent news conference.
The Argentine had not previously received a touchline sanction in his seven years in English football, which acted as a mitigating circumstance in the FA’s ruling.