Boulder prosecutors on Friday dropped the assault case against University of Colorado defensive lineman Josh Tupou, who was accused of starting a brawl on University Hill in February.

The Boulder County District Attorney’s Office filed a motion to dismiss the case against Tupou at a hearing at the Boulder County Jail.

County Judge Norma Sierra accepted the motion and released the bond for Tupou, who appeared out of custody.

“We are happy the Boulder District Attorney’s Office has decided to dismiss the charges at this time,” Jon Banashek, Tupou’s attorney, said after the hearing.

The motion stated that prosecutors moved to dismiss the case “without prejudice in order to continue to investigate.” Dismissing a case without prejudice means prosecutors can choose to re-file charges in the case at a later time.

District Attorney Stan Garnett said Friday that prosecutors “are investigating the fact pattern very thoroughly.”

Tupou, 20, turned himself in to the Boulder County Sheriff’s Office in March after a judge issued a warrant for his arrest on suspicion of second-degree assault, two counts of third-degree assault, criminal mischief, trespassing and reckless endangerment.

But at an April 1 hearing, Banashek said the accusations were a case of “mistaken identity” and expressed confidence the charges would be dropped.

According to the initial arrest affidavit, while at a party on the Hill in February, Tupou tackled a party guest, Christopher Tetreault, and punched him three to four times in the face.

Tetreault was transported to Boulder Community Health and suffered a broken nose and a broken bone in his right cheek.

Tupou also reportedly kicked another man in the crotch and then punched a third man in the back of the head, according to the affidavit.

Two other players, Jaleel Awini, 22, and Donovan Lee, 20, were issued misdemeanor summons in the case and are scheduled for hearings in the coming months.

At the time of the arrest and citations, CU officials said they would wait for the legal process to play out before deciding whether any action needed to be taken.

CU athletics spokesman Dave Plati said Friday that there has been no change in the players’ statuses as they still have student judicial hearings pending on campus.

Tupou, a junior from Buena Park, Calif., is a three-year starter as a defensive lineman for the Buffs. He recorded 42 tackles and three sacks while playing in all 12 games last season and was touted as an NFL prospect entering his senior season.

Lee, a freshman receiver, played in 10 games and had 13 catches for 78 yards and a touchdown in 2014. Awini was required to sit out last season after transferring to CU from Air Force.

Mitch Byars: 303-473-1329, byarsm@dailycamera.com or twitter.com/mitchellbyars