Two students are dead and one adult is in serious condition following a shooting at a Des Moines, Iowa school.

The shooting took place just around 1 p.m. at Starts Right Here, an educational mentorship program that helps at-risk youth in Des Moines. According to authorities, the shooting is the result of an “ongoing gang dispute.”

Preston Walls, 18, is in custody and has been charged with two counts of first-degree murder, attempted murder, and criminal gang participation in connection with the shooting. Two other unidentified individuals are in custody as well.

Starts Right Here is a program that works in conjunction with Des Moines Public Schools in credit recovery and behavioral support. According to the program’s website, classes are canceled for the remainder of the week but grief counselors are on hand.