The New Jersey police sergeant who secretly taped his former chief using the N-word baited him and then deleted tapes that could have provided context, the chief's defense attorney says in court papers filed this week in U.S. District Court in Camden.

The allegation was made by attorney Rocco Cipparone Jr. in a motion to dismiss charges against former Bordentown Township Police Chief Frank Nucera Jr., who is nearing a trial on suspicion of slamming the head of a handcuffed African American suspect into a door jamb because of racial bias in September 2016.

The prosecution intends to use more than 100 hours of tape-recorded conversations in which Nucera repeatedly used racial slurs. In one of the tapes, he is heard saying: "These n–s are like ISIS, they have no value.  They should line them all up and mow 'em down.  I'd like to be on the firing squad, I could do it."

In his motion, Cipparone said the tapes made by Police Sgt. Nathan Roohr were flawed because Roohr asked leading questions and then deleted potential evidence that the chief could use in his defense.  In one tape, Roohr is heard saying he was afraid "Black Lives [Matter] gonna be protesting on my front lawn" because of the assault.

A hearing on the motion is expected to be heard in the fall after the U.S. Attorney's Office files a response.

The 215 pages of court documents that Cipparone filed also say that six other police officers in the department taped Nucera beginning in 2014.

"Clearly there was a concerted effort to 'get' Frank Nucera out as police chief by officers" who were dissatisfied with his overtime pay policies and disciplinary actions, Cipparone said in the filing.

The documents also revealed that Nucera, 61, had been investigated by the FBI in an unrelated probe in 2007- 08.

Cipparone declined to elaborate on the subject of that investigation.  "I do not want to comment beyond the attachments to the motion," he said.

But the documents say that decade-old investigation was triggered by Jake Archer, an FBI agent assigned to the Philadelphia Division who previously was an officer on the Bordentown Township force.

Archer is a "good friend" of Roohr's and later brought Roohr's tapes to the attention of the FBI, which triggered the charges against Nucera, the court papers say.  Archer also defeated Nucera in a race for a seat on the township's Board of Fire Commissioners in 2007.

The filing also seeks to have the judge order two trials in the case: The first to determine whether the former chief is guilty of assaulting Timothy Stroye, who was arrested for failing to pay a hotel bill at the local Ramada, and a second trial — if Nucera is convicted in the first trial — to determine whether the attack was racially motivated.

"Using racially insensitive language by itself is not a crime, and without the assault there was no crime," Cipparone said.  He said he didn't want the jury to be prejudiced by the charges of racial animus before it decides whether Nucera attacked Stroye.

The federal indictment says that Roohr and another officer escorting the handcuffed Stroye, then 18, to a police cruiser both witnessed the assault.

Federal prosecutors say the chief slammed the Trenton teen's head into a metal doorjamb, causing "a loud thud" heard by witnesses, as he was being escorted out of the hotel.  Authorities said the attack was racially motivated.

In a statement to police, Stroye said that he could not identify the person who struck him and had difficulty seeing because he had been pepper-sprayed.

But Stroye said that he also recalled hearing someone say "chief" during the incident, and that after he was brought to the station, he heard the chief tell an officer: "If you got to, punch on him."