Irell & Manella has handled some interesting litigation lately for the uber-billionaire William Koch, including a suit claiming that Koch was duped into buying wine that once supposedly belonged to Thomas Jefferson. Now Irell partner and former Enron prosecutor John Hueston is playing defense for Koch, hoping to fend off bizarre-sounding claims that the Oxbow Group founder detained an Oxbow executive in an Old West ghost town on his Colorado ranch.

The plaintiff, a former senior vice president at Oxbow Carbon & Minerals Inc. named Kirby Martensen, sued Koch in October, claiming he was falsely imprisoned in March on Koch’s Bear Ranch near Aspen after being lured there on false pretenses. According to Martensen’s complaint in U.S. district court in San Francisco, Koch invited him for business meetings and to tour the full-size Western town he built on the ranch. But Martensen claims he was holed up in a small room in the town and questioned by two Koch agents for several hours about an alleged kickback scheme, and then kept under guard and hustled off to California in the middle of the night on a private plane.

The complaint alleges that Koch’s plan was "to intimidate and discredit [Martensen] for the purpose of chilling his speech and damaging his credibility," after Koch discovered Martensen’s concerns about a scheme to avoid paying taxes on $200 million in company profits. Martensen claims that as he was being escorted off the ranch he was fired and served with a complaint in a lawsuit against him and two colleagues. That suit, filed by Oxbow in Florida state court in March, accuses Martensen of "a wide-ranging scheme to systematically misappropriate revenues and business opportunities" by accepting bribes and diverting freight to an Oxbow competitor.

In a motion to dismiss filed Wednesday, Irell’s Hueston asked San Francisco federal magistrate judge Jacqueline Scott Corley to toss Martensen’s false imprisonment claims, arguing that he’s "a disgruntled former employee of the Oxbow companies who may have been embarrassed and upset that his corporate wrongdoing was discovered."

In an interview on Thursday, Hueston called Martensen’s San Francisco complaint "a frivolous, desperate attempt" to divert attention from the allegations against him in the Florida case. Hueston, who serves as Oxbow’s co-counsel with Stearns Weaver Miller Weissler Alhadeff & Sitterson, said Martensen’s false imprisonment allegations are already being addressed in discovery and depositions in the Florida case.

Martensen’s lawyer, John Houston Scott, did not immediately respond to a call seeking comment. Martensen is represented by Lewis Brisbois Bisgaard & Smith in the Florida case. In August, the Florida court denied Martensen’s motion to dismiss that action for lack of personal jurisdiction and improper venue.

Correction: An earlier version of this story referred to a suit that Koch brought over wine that supposedly belonged to Thomas Jefferson as "unsuccessful." An Irell spokesperson pointed out that the firm won its case against the seller in U.S. district court in Manhattan in November, including compensatory and punitive damages. We regret the error.