Authorities have not provided details about the motive of the shooter who opened fire on Border Patrol agents at an annex site in Texas Monday.

The incident took place at the entrance of the U.S. Border Patrol sector annex in McAllen, a city in southern Texas that borders Mexico, according to the DHS spokesperson. Mosqueda fired dozens of rounds toward the building and agents inside, Rodriguez said.

A Michigan man, Ryan Louis Mosqueda, fired on a U.S. Border Patrol station in Texas, injuring three and dying in the return fire. His motive is unclear, but his family cited past mental health issues.