Leeds face possible disciplinary action from the Football Association after objects were thrown from the terraces during Sunday's home win against Middlesbrough.
Missiles were thrown in the direction of a linesman by Leeds fans after referee Keith Stroud's controversial decision to award Boro a second-half penalty and the FA have launched an investigation.
The FA confirmed to Press Association Sport that it will be asking the West Yorkshire club for their observations.
Middlesbrough striker Britt Assombalonga converted the 76th-minute spot kick - Leeds defender Luke Ayling was deemed to have fouled Daniel Ayala - after Stroud's assistant had flagged for his attention.
A section of Leeds fans were incensed that Ayala had not been penalised for hauling down Ayling, who retaliated by grabbing the Boro defender's leg.
Leeds held on to secure a 2-1 win for their first Sky Bet Championship success in four matches, while the first return to Elland Road of Boro boss Garry Monk made for a feverish atmosphere.
Monk quit Leeds at the end of May following owner Andrea Radrizzani's takeover and was appointed as Boro manager just over two weeks later.