An indicted narcotics officer who served on a New Orleans-based federal drug task force contends he should stand trial separately from a colleague who has cooperated extensively with the government and already admitted to an array of misconduct.

An attorney for Karl E. Newman, a former Tangipahoa Parish Sheriff's Office deputy, asked a federal judge this week to sever Newman's proceedings from those of Johnny Domingue, a fellow former member of a U.S. Drug Enforcement Administration task force under investigation by the FBI.

Domingue, who also worked for the Tangipahoa Sheriff's Office, pleaded guilty this year to state drug conspiracy charges, but he also was named in a federal indictment that charged Newman with nine counts, including robbery, carrying a firearm during a crime of violence and possession with intent to distribute cocaine and oxycodone.

Newman also is accused of falsifying reports regarding the seizure of cash and tampering with a witness in a federal drug case. Domingue, by contrast, faces a lone federal charge of falsifying an investigative report. 

The two former deputies were charged as part of a widening Justice Department investigation into the theft of drugs and cash involving the DEA task force.

The FBI has been looking into a number of cases involving the task force, including some dating back over a decade, according to several sources familiar with the inquiry. The investigation continues, the sources said, and the FBI as recently as this week interviewed a federal prisoner concerning his dealings with the DEA.   

The investigation has resulted in the indefinite suspension of DEA Special Agent Chad Scott, a prolific narcotics officer who also began his lengthy law enforcement career in Tangipahoa Parish. Two of Scott's colleagues at the DEA's New Orleans field division were recently placed on limited duty, including a high-ranking supervisor, James "Skip" Sewell.

Newman's attorney, Ralph Whalen, argued in new court filings that Newman and Domingue would present "mutually antagonistic and exclusive defenses at trial." Based on the indictment, he added, it does not appear the charges against the two men are "connected." 

"It is clear ... that Domingue will be a witness against Karl Newman, in fact, the government's star witness," Whalen wrote in a court filing. "An essential element of Mr. Newman’s defense will be the crimes committed by Domingue. The defenses of these two defendants could not be more antagonistic."

Federal prosecutors have not responded to Whalen's motion. U.S. District Judge Eldon Fallon set a Jan. 12 date to hear arguments on the filing. The trial is scheduled for Feb. 6. 

In a telephone interview Thursday, Whalen said he expects Domingue to negotiate a plea agreement in the federal case, as he did in state court. 

"We know from testimony in bail hearings and the detention hearing that Domingue is the star witness," Whalen said. "It's inconceivable that they would ever be co-defendants."

Follow Jim Mustian on Twitter, @JimMustian.