A 17-year-old Catalina Magnet High School student was arrested Tuesday after an incident in the morning that sent the school into lockdown.

Tyler Renfro was booked into the Pima County jail on suspicion of aggravated assault and participating in a street gang while committing an aggravated assault, said Sgt. Chris Widmer, a Tucson Police Department spokesman.

Shortly after 8 a.m., 45 officers were dispatched to the campus after a report of a student on campus with a gun, Widmer said. The school at 3645 E. Pima St. was contained and the lockdown remained for 2 1/2 hours, while officers searched the campus.

"We actively prepare for these types of calls, and although it wasn't an active shooter call, we treated it very seriously and we put a plan into motion," Widmer said.

Detectives found out that Renfro and an 18-year-old Catalina High student were near the baseball dugout shortly after 8 a.m., and both were involved in an altercation, Widmer said.

Renfro pulled out a weapon, and it was later determined to be an Airsoft gun — a replica of a firearm that shoots pellets, Widmer said.

"The victim realized it wasn't a real gun, then Renfro pulled out a pocket knife and threatened the victim," said Widmer.

The primary witness was a TUSD employee at the school who reported the incident to school officials who then called 911, said Widmer.

The students involved dispersed and when officers arrived they searched the campus.

As officers searched the campus, Renfro came forward and told investigators that he was a witness. During questioning, police found out he was the suspect, Widmer said.

The victim eventually came forward and approached police and said he was involved in the incident, Widmer said.

A third student, who was detained off the school grounds as he was coming onto the campus, was a witness in the case, Widmer said. The age of this student was not available.

The Airsoft gun was found off campus, Widmer said. The knife was not found, he said.