An attorney for first son Hunter Biden attacked House Ways and Means Committee Chairman Jason Smith (R-Mo.) in a mistake-filled letter Friday, claiming the panel was coordinating with IRS whistleblowers on a “misinformation campaign to harm” his client.

Abbe Lowell, a high-profile Washington, DC, defense attorney who joined Hunter’s legal team late last year, accused Smith, Judiciary Committee Chairman Jim Jordan (R-Ohio) and Oversight Committee Chairman James Comer (R-Ky.) of basing House investigations into the first son on “unsworn and slanted statements” by IRS supervisory agent Gary Shapley and another anonymous investigator.

Lowell suggested the IRS workers made their disclosures to Congress “in an attempt to evade their own misconduct,” saying both they and Smith had violated federal laws in making public statements about the probe.