The Senate Intelligence Committee is continuing its efforts to obtain documents from former national security adviser Michael Flynn, after he refused to comply with a committee subpoena this week in its investigation of Russia interference in the 2016 election.

Intel committee Chair Richard Burr (R-NC) and Vice Chair Mark Warner (D-VA) announced Tuesday after a closed door committee meeting that they would be sending a written response to Flynn’s lawyers, questioning their rationale for invoking his 5th Amendment right against self incrimination as the basis for not complying with the committee’s subpoena of his documents.

They committee leaders also said they were in the process of sending subpoenas to two of Flynn’s businesses, seeking additional documents. The lawmakers said they did not believe the businesses could invoke the 5th Amendment.

“While we disagree with General Flynn’s lawyers interpretation of taking the 5th, it is even more clear that a business does not have the right to take the 5th if it’s a corporation,” Warner said.

The two Flynn businesses that will be issued subpoenas, according to Warner, were Flynn Intel, LLC and Flynn Intel, Inc.

The letter the committee sent to Flynn’s lawyers would also address claims by the lawyers that the committee’s document requests lacked specificity, Burr said.

“We have been very specific in the documents now that we have requested from General Flynn,” he said.

Burr did not rule out further steps, including holding Flynn in contempt, if he continued to refuse to comply.

“We have taken the actions that we feel are appropriate right now,” Burr said. “If in fact there is not a response, we will seek additional counsel and advice on how to proceed forward. At the end of that option is a contempt charge, and I’ve said that everything is on the table. That is not our preference today.”

Burr also explained why the committee is not considering offering Flynn immunity. “It’s a decision that the committee has made that we are not the appropriate avenue in a potential criminal investigation,” Burr said. “As valuable as General Flynn might be to our counter intelligence investigation, we do not believe that it is our place today to offer him immunity from this committee.”