Can he be threatened with imprisonment as is done with recalcitrant witnesses?

The Supreme Court said in 1821 that Congress has "inherent authority" to arrest and detain recalcitrant witnesses.

But sometimes, Larry explained, recalcitrant witnesses soften up in the presence of people with whom they feel a strong emotional connection.

She was able to persuade recalcitrant witnesses to speak when his own size and naturally intimidating features inclined them to refuse.

The Supreme Court said in an 1821 case that Congress has the "inherent authority" to arrest and detain recalcitrant witnesses.