Sebastian Gorka, President Donald Trump's recently ousted deputy assistant and strategist, needs to be investigated for potentially lying about his alleged ties to a neo-Nazi group, Senate Minority Whip Dick Durbin said Saturday.

Gorka submitted his resignation on Friday. Durbin, D-Ill., tweeted that he would like to see Gorka investigated, even though he is no longer working for the government.

.@SebGorka should never have been an advisor to @POTUS. He should still be investigated for concealing neo-nazi ties. https://t.co/6JzDJJ7UlY — Senator Dick Durbin (@SenatorDurbin) August 26, 2017

Durbin was responding to a tweet he posted earlier this month, in which he raised the possibility that Gorka did not disclose his alleged ties to a Hungarian neo-Nazi group.

Did @SebGorka fail to disclose ties to neo-nazi group on his U.S. naturalization application? We again asked @TheJusticeDept and @DHSgov. pic.twitter.com/G6iUkPyESw — Senator Dick Durbin (@SenatorDurbin) August 21, 2017

Gorka was close to Steve Bannon, who served as Trump's chief strategist before he resigned Aug. 18. There were rumors after that that Gorka could be the next member of Trump's inner circle to leave his post.