NEWARK -- The police officer who used racial slurs when investigating a brutal attack caught on a "nanny-cam" in a Millburn home in 2013 will not face criminal charges, acting Essex County Prosecutor Carolyn A. Murray said in a release Friday.

Sean Curtis was convicted of severely beating a Millburn woman in May, based largely on evidence of the attack caught on a nanny-cam video. During his trial, it was revealed that the nanny-cam also picked up racial slurs used by investigating detective Colin McMillan in reference to Curtis.

"Those comments did not rise to the level of criminal conduct," the prosecutor's office said in the release. McMillan may, however, still face administrative charges from the Millburn Police Department, Murray said.

The nanny-cam video, which captured an African-American man beating a woman and throwing her down the stairs in front of her three-year-old daughter during a home invasion, also recorded McMillan, who is white, uttering racial epithets to other officers. The comments prompted questioning during Curtis's hearing about whether or not McMillan was fit to investigate the incident.

During the trial, McMillan apologized for his comments, noting that he had been placed on administrative duties in the police department since they came to light.

In June, Curtis was found guilty of aggravated assault, robbery, endangering the welfare of a child, and criminal restraint. He was acquitted of an attempted murder charge. He has been sentenced to life in prison plus five years in connection with the beating.

Jessica Mazzola may be reached at jmazzola@njadvancemedia.com. Follow her on Twitter @JessMazzola. Find NJ.com on Facebook.