Mueller, the special counsel examining alleged Russian interference in the 2016 presidential election, removed FBI agent Peter Strzok from the investigation over the summer, according to The New York Times.
"I am concerned, however, that our chairman is willing to use the subpoena and contempt power of the House, not to determine how the Russians interfered in our election or whether the president obstructed Justice, but only to distract from the core of our investigation", Schiff said.
A spokesperson for the special counsel's office, Peter Carr, said "Immediately upon learning of the allegations, the special counsel's office removed Strzok from the investigation", reported New York Times.
The agent, Peter Strzok, is considered one of the most experienced and trusted FBI counterintelligence investigators. Although Strzok's departure from the investigation was reported by ABC News in August, the reason behind the move was unclear until now. Multiple outlets report he's now working in human resources.
One of the only times I've ever seen my father, a career military man and Vietnam veteran, express genuine concern over the direction of our country was in the wake of the FBI's fall from grace under James Comey. Trump has called the probe a "witch hunt", while Russian President Vladimir Putin has said the accusation is the result of Clinton's supporters not wanting to admit the Democratic candidate has only herself to blame for losing the election. But following the news, analysts pointed out that his reassignment suggests that Mueller has worked to avoid any conflicts of interest.
Strzok was removed this summer after the inspector general of Justice Department discovered him and another person from Mueller's team exchanging anti-Trump text messages.
The House committee's top Democrat, Rep. Adam Schiff of California, responded in a statement that the Department of Justice inspector general is "properly investigating the handling of the investigation, including the current allegation of bias" by Strzok.