Etowah County Sheriff Jonathon Horton said that a man, identified as 32-year-old Robert Tyler White, arrived at Walnut Park Elementary in Gadsden, Alabama, around 9:30 a.m. Thursday morning.

According to Gadsden City Schools superintendent Tony Reddick, White “aggressively” attempted to enter the school, checking several doors to see if they were unlocked. His suspicious activity prompted a lockdown. Several dozen students were at the school at the time.

The Alabama Law Enforcement Agency said in statement that White then attempted to enter a vehicle belonging to the school resource officer, which triggered an altercation with the officer. At some point, White allegedly attempted to take the officer’s weapon.

The altercation ended with White being shot and killed.