A gunman attacked a father and son Monday morning inside an office building near Medical City.

The attack happened just after 11 a.m. on the third floor of the United Texas Bank building at 12222 Merit Drive. NBC 5 is reporting that when police arrive at the building, they encountered the gunman in the hallway, and gunfire was exchanged between him and police. The gunman then retreated back into one of the offices, and then shot himself in the head, police believe. The gunman is now at Baylor in critical condition.

The father and son, 63 and 39 respectively, are both in stable condition at Parkland Hospital. They both worked for a financial services company in the building and knew the gunman, police said. The motive for the shooting has not yet been established, and the names of the gunman or the victims have not been released.