The Football League have been investigating whether or not to act after the Leeds boss confessed to sending a staff member to spy on Derby County's training.
United have been under scrutiny from both the EFL and the Football Association since a scout working for head coach Marcelo Bielsa was questioned by police after being stopped outside Derby County's training ground on January 10.
"I've already said that I'm the one responsible", Bielsa previously said in a previously arrange press conference.
Leeds, who are chasing promotion to the Premier League, had been desperate for a quick conclusion, but the matter was unable to be resolved at Friday's EFL meeting, which was not attended by officials from Leeds or any of their Championship rivals. Some say it was cheating.
The EFL, who had last month contacted Leeds for further clarification over the incident, released a statement on Friday night.
"Following a comprehensive review of all available evidence, it was determined that there remain a number of areas that require further exploration and clarification and these investigations will take place at the earliest opportunity".
"An update on this matter will be provided following receipt and analysis of those subsequent enquiries and until this point no further comment will be made".
Bielsa and the scout concerned have been interviewed by the FA and Leeds responded to a request for information from the EFL at the beginning of last week.
In response, a statement from the Yorkshire club read: 'Leeds United acknowledge the statement made by the EFL this evening regarding an incident at Derby County's training ground in January.
Derby, Bristol City and Norwich were among 11 Championship clubs to have signed a collective letter sent to the EFL demanding a full inquiry.
At the time their irate manager Frank Lampard believed the club should be disciplined, despite Bielsa's admission.