16-year-old suspect charged with first-degree murder after Maryvale High School stabbing

PHOENIX — A teen accused of fatally stabbing another student at Maryvale High School last week has been formally charged, authorities announced Thursday.

A Maricopa County grand jury indicted 16-year-old Chris Aguilar on one count of first-degree murder on Tuesday, according to court documents.

Aguilar is accused of attacking 16-year-old Michael Montoya II first with his fists, then with a pocketknife that police later recovered outside. Montoya was taken to a hospital, where he died from his injuries.

Maricopa County Attorney Rachel Mitchell has said Aguilar will likely be prosecuted as an adult under the state law on violent crimes with defendants aged 15-17.

🔪 Maryvale High School Stabbing Update

Maricopa County Attorney Rachel Mitchell says 16-year-old Chris Aguilar, pictured below, will be charged as an adult for allegedly fatally stabbing classmate Michael Montoya II, who had reportedly stolen Aguilar’s firearm the day before.… pic.twitter.com/tYlT3NyzeE

— KTAR News 92.3 (@KTAR923) August 21, 2025

The assault took place inside one of the classrooms at the high school, which is near 59th Avenue and Osborn Road, around 10:54 a.m. on Aug. 19, the Phoenix Police Department said.

After Aguilar was detained, he was taken to a different hospital than Montoya for treatment for a bleeding hand. No other students or staff members were injured in the incident, according to police.

Suspect Maryvale High School stabbing formally accused of first-degree murder

ABC15 obtained court documents that suggest a possible motive for the fatal Maryvale High School stabbing. The outlet reported that Montoya allegedly stole a firearm from Aguilar a day before the attack.

After the robbery, the suspect and his brother were allegedly heard saying they would kill Montoya, ABC15 reported.

Students at Maryvale High School were shifted to virtual learning for the remainder of the week after the stabbing, but they returned to campus on Monday.

However, the transition has not been seamless, particularly amid concerns over how a pocketknife bypassed the school’s metal detection systems.

On Monday, a state lawmaker allegedly tried to test these security systems by entering the high school’s front office with a boxcutter, according to a Wednesday announcement from the Phoenix Union High School District.

Two members of the Phoenix City Council, as well as Arizona’s top education official, have called for her to resign from public office as a response to her alleged stunt.

Related

Lawmaker accused of bringing box cutter to Maryvale High School to 'test' security systemFormer teacher says Phoenix district concealed safety issues before deadly school stabbingCourt documents reveal possible motive for deadly knife attack at Maryvale High SchoolMaricopa County announces 6 new measles exposure sites in Chandler, PhoenixDave Ramsey says: You’re really just trading one expense for anotherDOJ monitoring polling sites for voting rights compliance in 3 Arizona counties on Election Day