(CNN) An investigation into an encounter between Kentucky high school students and Native American activists has found "no evidence of offensive or racist statements" by the students, according to a report posted on the Diocese of Covington website.

The Native American man was at the memorial for the Indigenous Peoples March, and the students had attended the March for Life rally.

A second video later surfaced showing another group, which identifies itself as members of the Hebrew Israelites, taunting the mostly white students with disparaging and vulgar language before the January 18 encounter with Phillips.

The investigative report was prepared by Greater Cincinnati Investigation, a detective agency retained by a law firm on behalf of the diocese and the school. It said the students never responded to the Black Hebrew Israelites with racist or offensive statements and never chanted "Build the Wall," as some alleged at the time.

Bishop Roger Foys, whose diocese initially condemned the actions of the students , said in a letter to parents on Monday that the teenagers have been exonerated.

"Our inquiry, conducted by a third party firm that has no connection with Covington Catholic High School or the Diocese of Covington, has demonstrated that our students did not instigate the incident that occurred at the Lincoln Memorial," Foys said.

Th bishop said the teens "were placed in a situation that was at once bizarre and even threatening" and their reaction was "expected and one might even say laudatory."

'Some students performed a tomahawk chop'

In the video, student Nick Sandmann was featured prominently facing Phillips. Some students wore "Make America Great Again" hats and surrounded Phillips, who played a drum and chanted, as Sandmann stared at him.

The report said investigators did not take Sandmann's statement in person. Investigators also made numerous attempts to reach Phillips, including traveling to his home and waiting for him for six hours, but they did not get a response from him.

At the time, the report said, the students reportedly thought Phillips was coming to join their cheers and did not feel threatened.

"We found no evidence of offensive or racist statements by students to Mr. Phillips or members of his group," the report said.

"Some students performed a 'tomahawk chop' to the beat of Mr. Phillips' drumming and some joined in Mr. Phillips' chant."

There was no immediate comment from Phillips.

Sandmann's attorney, Lin Wood, said via Twitter that the report "unequivocally exonerates Nick Sandmann & refutes the vicious lies by the mainstream & social media mob against this 16-year old student & his classmates."

"Nick Sandmann is owed apologies from thousands of accusers & accountability for damage to his reputation & threats against his life," he wrote in a series of tweets that included the report. "Criminal prosecutions & civil lawsuits will teach members of the mob a lesson they will never forget.

Jerome Bowles, president of the Northern Kentucky NAACP, told CNN on Wednesday that the diocese needed to "take a serious look at itself" on issues of diversity, community outreach and cultural competence.

"There's always an opportunity to say some things could have been done differently," he said.

"We need to see if we're preparing our students for the wider world. An institution can be academically successful but culturally incompetent."

Chaperones 'did not feel' students were threatened by Phillips

The report said students performed cheers common at football and basketball games to drown out the Black Hebrew Israelites.

Chaperones at the encounter between Phillips and Sandmann told investigators "they did not feel the students were threatened by Mr. Phillips or his group."

Most students wearing MAGA hats bought them the day of the March for Life, according to the report. Chaperones told investigators that some students had purchased "Hope" hats in support of President Barack Obama in years past.

The report said four licensed investigators spent about 240 person hours reviewing the incident. They interviewed 43 students, 13 chaperones, and reviewed evidence such as online videos and social media posts.

Phillips told CNN after the video went viral that he felt hatred from the young people in the crowd. When asked about Sandmann standing in front of him, Phillips said he was trying to retreat and the only way he could do so was to go forward.

"When I started going forward and that mass of groups of people started separating and moving aside to allow me to move out of the way or to proceed, this young fellow put himself in front of me and wouldn't move," Phillips said.

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Sandmann denied the characterizations of his and his classmates' behavior and said he was simply standing before Phillips to let him know he wouldn't be baited into an altercation. He also said he was not disrespectful to Phillips.

After initially condemning the behavior of the students, the Catholic diocese later said it was "bullied and pressured" into a making a premature statement about a viral video.

Foys said in the letter last month that the leadership of the Diocese of Covington was "being pressured from all sides to make a statement" about the video.

"We are sorry that this situation has caused such disruption in the lives of so many," Foys wrote. "We apologize to anyone who has been offended in any way of our statements which were made with good will based on the information we had. We should not have allowed ourselves to be bullied and pressured into making a statement prematurely, and we take full responsibility for it."

Foys wrote that Covington students and their families had received death threats.

The original January 19 statement said the diocese condemned the actions of the students and issued an apology to Phillips.