RALEIGH, N.C. -- Police filed charges Friday against three people accused of helping tear down a century-old Confederate statue during a protest this week at North Carolina's flagship university. The charges came as a member of the University of North Carolina Board of Governors said the monument known as Silent Sam will be reinstalled on the Chapel Hill campus within 90 days, CBS Raleigh affiliate WNCN reported.

Orange County District Attorney Jim Woodall confirmed to WNCN that three people face charges of misdemeanor riot and misdemeanor defacing of a public monument. The UNC police department said the three aren't affiliate with the university.

The suspects hadn't been arrested as of Friday afternoon, said UNC police spokesman Randy Young, who declined to immediately release their names.

Police wearing riot gear guard a statue of a Confederate soldier nicknamed Silent Sam on the campus of the University of North Carolina during a demonstration for its removal in Chapel Hill, N.C., on Tue., Aug. 22, 2017. Reuters

The department said there could be more arrests. Another protester was charged earlier in the week with misdemeanor counts of resisting officers and wearing a mask shortly before the statue came down.

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Several hundred protesters on UNC's campus in Chapel Hill used ropes Monday night to bring down the statue. The organized protesters took advantage of a non-confrontational police response to topple the statue that stood since 1913 in a main quad.

Demonstrators started their rally across the street, before marching over and surrounding the statue. To outwit officers, the protesters raised banners concealing efforts to tie a rope around the sculpture. They then split into two groups. Most marched away as a small group remained behind. The banners were up for about an hour before the groups converged and yanked the statue down, according to videos.

The police response Monday was much different from the response to a similar protest a year ago. In 2017, officers in riot gear faced criticism for heavy-handed tactics after using metal barricades to keep activists from getting near the statue. The portable barriers weren't used Monday, and officers didn't keep protesters away from the statue.

University and legislative leaders have condemned the protesters' actions as "mob rule," demanding a hard look at the police response and a full criminal investigation. The State Bureau of Investigation has been brought in to assist.

Republican state Rep. Bob Steinburg said in an interview Friday that he felt the misdemeanor charges filed so far were insufficient.

"That's a relative slap on the hand based on what they have done," he said.

Steinburg said he's worried that weak prosecution of vandals will embolden further attacks on other Confederate monuments across the state. He called law enforcement responses to Silent Sam and another statue toppling in Durham "milquetoast."

Last year in Durham, demonstrators tore down a Confederate statue in front of local government building. Law enforcement officers took video but didn't try to stop them as one climbed a ladder and attached the rope that was then yanked by protesters on the ground.

A judge in Durham later dismissed charges against two and found a third not guilty because of difficulty identifying protesters on video. The district attorney then dropped charges against the remaining five, saying he didn't have any stronger evidence against the rest.

In Chapel Hill, university leaders have noted the protest Monday was highly organized and "unlike any" they'd seen before. On Thursday, Chancellor Carol Folt told reporters university officials had expected a smaller demonstration and were taken by surprise.

The statue is in temporary storage, and its future is unclear.

Before it was torn down, it had been under constant, costly police surveillance after being vandalized in recent months. Many students, faculty and alumni argued that "Silent Sam" symbolized racism and asked officials to remove it.