The FBI on Tuesday confirmed it found a cooler with bottles of sulfuric acid in a storage unit that was searched overnight in north Harris County as part of its investigation into the deadly New Orleans attack.

The sheriff’s office said the victim, a 19-year-old, died at the scene, while his brother, believed to be 16 or 17, was taken to the hospital.

Investigators said when the detention officer was arrested, he reeked of alcohol and appeared intoxicated. He has now been placed on administrative leave pending the outcome of the investigation.