(DES MOINES, Iowa) — Two students have died after a shooting at their Des Moines, Iowa, school on Monday, according to police.

The third victim, a school employee, is in serious condition after the shooting at Starts Right Here, a charter school, Des Moines police spokesman Paul Parizek told reporters.

Police later said the injured victim is 49-year-old Altoona resident William Holmes, the founder and CEO of Starts Right Here. He remained hospitalized in serious condition as of Monday night, according to police.

The shooting, which took place inside the school, was reported just before 1 p.m. About 20 minutes later, three potential suspects were taken into custody at a traffic stop about 2 miles away from the school, according to police.

The shooting was the result of an “ongoing gang dispute,” police said.

Preston Walls, 18, of Des Moines, has been charged with two counts of first-degree murder, attempted murder and criminal gang participation, police said. Two additional people remain in custody as the investigation continues, Parizek said.

The victims have not been identified, but police said they were two young men, 18 and 16 years old, respectively.

A motive is unclear, but Parizek said the shooting was “definitely targeted” and “not random.”

Des Moines Public Schools interim Superintendent Matt Smith said in a statement: “We are still waiting to learn more details, but our thoughts are with any victims of this incident and their families and friends. Starts Right Here is a valuable partner to DMPS, doing important work to help us re-engage students, and we stand by to support them during this critical time.”

Mike Beranek, president of the Iowa State Education Association, said in a statement: “We implore our elected leaders to consider effective strategies to eliminate gun violence and pursue concrete solutions that will keep our students, educators and communities safe. Our schools need to be bastions of safety, not the recipients of violence. This needs to end. As a nation, we need to recognize this is a societal issue seeping into our schools.”

A representative from the Des Moines Public Schools said Starts Here is a “community partner of Des Moines Public Schools providing two services: helping to re-engage students in the district’s Options Academy credit recovery program and supporting students no longer in a school building due to behavioral issues.” The school, which began its partnership with the district in 2021, serves between 40 and 50 students, the representative said.

Iowa Gov. Kim Reynolds said in a statement that she’s “shocked and saddened.”

She said she’s seen “first-hand how hard” the school staff “works to help at-risk kids through this alternative education program.”

“My heart breaks for them, these kids and their families,” the governor said.

Copyright © 2023, ABC Audio. All rights reserved.