Victoria Police was warned it could be criminally charged after admitting it had not given the Lawyer X royal commission more than 1000 documents about a former drug squad detective once charged over a double murder.

The documents relate to notorious ex-detective Paul Dale, questioned for several days in the inquiry, and should have been tendered to a commission supposed to shed light on the scandal.

Mr Dale was once charged with organising the murder of drug dealer and police informer Terence Hodson, who was slain with his wife in Kew in 2004.

Paul Dale leaves the royal commission last week. Credit:AAP

“[Mr Dale was subject to] Murder investigations, perjury investigations. There’s obviously a vast amount of material, not all of which is relevant to these proceedings,” the force’s QC Justin Hannebery said.