President Trump took aim once again Friday at Andrew McCabe, asking why the fired former acting FBI director is not “being investigated” over his political connections during the Hillary Clinton email investigation.

“Why isn’t disgraced FBI official Andrew McCabe being investigated for the $700,000 Crooked Hillary Democrats in Virginia, led by Clinton best friend Terry M (under FBI investigation that they killed) gave to McCabe’s wife in her run for office? Then dropped case on Clinton!” Trump tweeted.

Trump was referring to donations to Dr. Jill McCabe's 2015 Virginia State Senate campaign from a political action committee for then-Virginia Gov. Terry McAuliffe -- a longtime Clinton ally. According to The Wall Street Journal, the PAC donated $467,500, while the Virginia Democratic Party donated an additional $207,788 to McCabe's campaign.

McCabe was fired in March ahead of his planned retirement, putting his pension in jeopardy. The move came after the Department of Justice inspector general determined he lied about a media leak to investigators and to former FBI Director James Comey. Comey backed the findings of the DOJ watchdog, which also sent a criminal referral to the U.S. Attorney in Washington.

McCabe’s legal team vowed to fight any possible charges.

"Although we believe the referral is unjustified, the standard for an IG referral is very low. We have already met with staff members from the U.S. Attorney’s Office," McCabe's legal team said in response to the referral.

"We are confident that, unless there is inappropriate pressure from high levels of the Administration, the US Attorney’s Office will conclude that it should decline to prosecute," they said.

Trump’s tweet comes as his own legal team is stepping up criticism of Special Counsel Robert Mueller’s Russia probe, after the investigation hit the one-year mark.

Trump also weighed in again Friday on a New York Times report that said an unnamed government informant was in contact with Trump advisers during the 2016 campaign – fueling allegations about FBI spying.

"Reports are there was indeed at least one FBI representative implanted, for political purposes, into my campaign for president. It took place very early on, and long before the phony Russia Hoax became a 'hot' Fake News story. If true - all time biggest political scandal!" he tweeted.

Fox News' Brooke Singman contributed to this report.