A 16-year old high school student in the United States was shot dead at a hotel in Costa Rica by a security guard while mistaking him for a thief, authorities announced Thursday.

Justin Johnston, a high school senior in Kansas, was shot on his chest on Thursday at the La Cangreja Lodge in La Fortuna de San Carlos, Costa Rica. Johnston was in a school trip to Central America as a part of their school’s Spanish program. He was there with his schoolmates and school district sponsors.

Police said that all the students were sent to bed before 10 in the evening Wednesday but several of them left their rooms to go to another building in the area. They were walking back to their rooms before dawn Thursday when the security guard saw them. Thinking they were a bunch of thieves, the security guard open fired on them. None of the other students were harmed.

The 34-year old security guard identified as Guevara, is in the custody of the police.

Steve Splichal, McLouth School District Superintendent, said that their primary concern is the safety and security of their students. They have already arranged for the rest of the students to come back home early. Splichal said that they are also concerned about Johnston’s parents and all the other students involved in the crisis. He added that the district’s crisis plan has already been activated.

This is not the first time a student from northeast Kansas has been killed during an educational trip to Costa Rica. Shannon Lucile Martin was killed in 2001, days before her graduation, while walking back to her room in Golfito, Costa Rica.