The EFL has received a complaint from the Rams over the incident, which happened a day before Friday's Championship match, which Leeds won.

Argentine Bielsa, 63, took responsibility before the game.

The Football Association has already started its own investigation.

A Leeds staff member was seen acting suspiciously outside County's training ground last Thursday, with Bielsa saying he had instructed the unnamed employee to carry out the task.

Rams boss Frank Lampard described the incident as "bad" and said it had "disrupted" his side's build-up to the game.

Leeds formally apologised to Derby and subsequently reminded Bielsa "of the integrity and honesty" of the club.

The EFL has written to the Championship leaders, requesting their observations on the matter.

In a statement, the League said it would consider the matter "in the context of a number of EFL regulations", while also saying the alleged action "appears to contravene the club's charter" which all 72 EFL clubs agreed to in the summer of 2018.

The EFL will work with the FA to ensure that any potential action taken does not prejudice the governing body's investigation.

"It's up to how much the FA and EFL want to stop what happened happening again, or whether they don't," Lampard said on Monday.