Glenn Simpson, Partner of Fusion GPS, speaks on a panel at the Double Exposure Investigative Film Festival and Symposium on October 7, 2016 in Washington. http://doubleexposurefestival.com
Washington CNN  — 

The Judiciary Committee plans to force Fusion GPS co-founder Glenn Simpson to appear next week to plead the Fifth in response to a subpoena.

A Republican House Judiciary Committee aide told CNN the committee expects him to appear in compliance of the subpoena, even though Simpson’s lawyer said he wouldn’t answer questions before the panel.

House Intelligence Committee Chairman Devin Nunes used similar tactics when his panel subpoenaed Simpson last year, though he ultimately testified before that committee voluntarily.

Simpson rejected a House Judiciary Committee subpoena Thursday requesting he appear before the committee next week for a confidential deposition, according to a letter sent by his lawyers.

“He will instead invoke his constitutional rights not to testify under the First and Fifth Amendments of the Constitution,” the letter said.

In the letter, addressed to Committee Chairman Bob Goodlatte, Simpson’s lawyers question the motives of the committee’s investigation, asserting that the “inquiry is not designed to discover the truth.”

“The obvious – and at times explicitly stated – goal of this Committee is to discredit and otherwise damage witnesses to Russia’s interference in the 2016 election, all as part of an effort to protect a President who has sought to placate and curry favor with a hostile foreign power and who demands that the Justice Department stop investigating him,” the letter continues.

Since it was first alleged that Russia interfered in the 2016 election, there have been multiple investigations looking into possible collusion between Trump campaign associates and the Kremlin. President Donald Trump has repeatedly denied all accusations of collusion.

Fusion GPS is the firm that commissioned an opposition research dossier on Trump and Russia written by ex-British intelligence officer Christopher Steele, parts of which remain unconfirmed. Trump has dismissed the dossier as “fake” and “fraudulent.”

The letter claims the “Committee has repeatedly interviewed witnesses in secret, only to selectively leak from the interviews to disparage those witnesses and promulgate a patently false narrative.” It also notes that Simpson has previously testified before three congressional committees.

“The Committee has refused to define the scope of the deposition, but its members have already falsely accused Mr. Simpson of ‘lying’ – ample basis for us to be concerned that this Committee is only seeking to falsely incriminate Mr. Simpson,” the letter said. “Thus, the service of a subpoena on Mr. Simpson for a closed-door deposition by politicians who have already exhibited abundant bad faith leaves him with no other decision than to stand on his constitutional rights under the First and Fifth Amendments not to testify.”

The letter identifies the proposed date of the deposition as October 16. In late September, Simpson’s attorney sent a similar letter criticizing the committee when he declined a voluntary interview, which prompted the subpoena from Goodlatte.

Fusion GPS also waged a court battle over subpoenas from the House Intelligence Committees over the firm’s bank records last year. Simpson has testified before the House and Senate Intelligence committees and Senate Judiciary Committee.