NEWARK -- On the morning of June 21, 2013, Millburn Detectives Collin McMillan and Andrew DelRusso and other township police officers responded to a residence where an African-American man had attacked a woman during a home invasion and fled the scene.

A "nanny-cam" video in the house captured McMillan using racial slurs about the assailant on three occasions. While speaking with DelRusso at one point, McMillan referred to the attacker as a "monkey" and said the case would take precedence over his other cases.

DelRusso then replied, "Yup."

DelRusso testified about that exchange on Wednesday at a hearing for Shawn Custis, who has been on trial on attempted murder and related charges in connection with the attack. Custis is African-American.

The police sergeant said he did not recall hearing the racial slur when he was speaking with McMillan at the scene. DelRusso claimed the "Yup" was not in response to the epithet, but instead to McMillan's comment about the "nanny-cam" case taking priority over other cases.

DelRusso said he first heard the slur when he recently viewed the video, saying the remark was "completely shocking." If he had heard the "monkey" comment at the scene, DelRusso said he would have reported it to his superior officers.

"I don't know how I would miss him saying that, because it would be so glaring in my mind," said DelRusso, who said he had never heard McMillan utter racial epithets during their interactions.

DelRusso said McMillan seemed "visibly shaken" after seeing the victim, and DelRusso said he began "tuning him out."

"I know I was not listening to him the entire time at the scene," DelRusso said.

But Superior Court Judge Ronald Wigler granted a request from Custis's attorney, John McMahon, to have DelRusso testify at the trial and allow jurors to decide whether DelRusso was responding to the racial epithet or the comment about prioritizing cases.

"It's not for me to make that determination," the judge said.

The judge previously ruled McMillan, who is white, would be presented as a witness at the trial to address questions about the racial slurs, and Wigler said the portions of the video including the racial slurs would be played for the jury. Jurors have not viewed those portions yet.

The jury is scheduled to return on Monday to continue hearing testimony in the trial.

The "nanny-cam" video has always been the centerpiece of the case against Custis, 45, of Newark. Prosecutors have alleged the video shows him severely beating the victim and throwing her down the basement stairs in front of her 3-year-old daughter.

On the first day of the trial, the jury watched the portion of the video that includes the attack. At that time, McMahon questioned why that video clip stopped at a certain point.

Last week, Essex County Assistant Prosecutor Jamel Semper, who is trying the case, reviewed all of the "nanny-cam" footage held by the prosecutor's office and discovered the portions including the racial slurs, according to Wigler. Semper then immediately informed McMahon about those portions, the judge said.

Now, McMahon is looking to use those portions to cast a cloud of suspicion over the investigation in the case. McMahon has argued McMillan's colleagues must have known he is a "racist," and he questioned why McMillan was allowed to work on a case involving an African-American suspect.

"It taints everything," McMahon said at an earlier hearing on Wednesday.

But Wigler said on Wednesday that he had reviewed the personnel and internal affairs files of McMillan, DelRusso and Millburn Police Officer Joao Rebelo, who also was present at the scene, and found "absolutely nothing" that would suggest the officers were racially biased.

On the witness stand Wednesday, Rebelo testified that he did not recall hearing McMillan or any other member of the township police department use a racial slur uttered by McMillan in the video.

"I have never heard anyone in the department use that word," Rebelo said.

Rebelo visited the house for the "nanny-cam" investigation and he can be seen on the video, but he testified he does not recall hearing McMillan utter the racial epithets at that time. Rebelo said he first heard the slurs when he watched the video on Wednesday.

"When I watched the video today, I was very shocked," Rebelo said. "I have never heard him use any racial slurs before until today."

Bill Wichert may be reached at bwichert@njadvancemedia.com. Follow him on Twitter @BillWichertNJ. Find NJ.com on Facebook.