WASHINGTON ― After President Donald Trump’s national security adviser Michael Flynn was forced to resign over his contacts with Russia, Sen. Al Franken (D-Minn.) argued that the Senate needs to know a lot more about all of the Trump administration’s ties to Vladimir Putin’s government.

Flynn quit after reports surfaced that he talked repeatedly to the Russian ambassador to the United States about the sanctions levied against Russia, which Flynn had denied.

That lie is the first problem for Franken.

“The National Security Advisor is entrusted with making sure the President has the best possible information to defend us from foreign threats and protect our country,” Franken said in a statement. “Gen. Michael Flynn was clearly not the right person for that job.”

But, the senator said, echoing other Democrats and some Republicans, Congress can’t stop with investigating Flynn.

“While I’m relieved that Gen. Flynn has resigned his post, I don’t believe that this case is closed,” he said. “We must pursue independent, bipartisan, and comprehensive investigations into what the Trump Administration knew about General Flynn’s problematic contact with Russia, when they knew it, and why the public was misled.”

“The American people also deserve to know the full extent of the President and his team’s ties to Russia. Let’s give them that information,” Franken continued.

So far, Senate and House GOP leaders have suggested that any investigation of Flynn can be handled by existing committees, most likely the intelligence committees.

Such a proceeding may or may not be public, and it’s unclear how broadly the committees would be willing to look.

Franken sits on the Senate Judiciary Committee, which would have jurisdiction over the Department of Justice and any criminal matters related to Flynn.

UPDATE: Franken made his initial remarks before the news broke Tuesday night that the Trump campaign had many contacts with Russian intelligence officials.

On Wednesday, he sounded a louder alarm.

“Let me be very clear: Russia wants to subvert our democracy, and its close ties with the President and his staff raise several red flags,” Franken said.

The senator suggested one way for Trump to quickly clear up at least some of the worries that the president may be beholden to Putin.

“He must immediately release his tax returns,” Franken said.