> Sr. Cpl. Banes said they considered using a .50 caliber rifle to fire at the shooter, which had been successful in a similar attack on police 14 months earlier. However, in that case, the suspect had driven an armored truck into police headquarters and remained inside the armored vehicle. Johnson was holed up inside a populated college with thin sheetrock walls, so the tactical team deemed that approach too dangerous. They also considered rappelling down the building or attacking Johnson through the ceiling after opening it with explosives. Both options were ruled out due to the risks they might pose to the officers who would carry it out.
> Senior Corporal Jeremy Borchardt and others ultimately arrived at the idea to use a bomb disposal remote control vehicle armed with about 1 pound (0.45 kilograms) of C-4 explosive. The plan was to move the robot to a point against a wall facing Johnson and then detonate the explosives. The device exploded as intended at approximately 2:30 a.m., killing Johnson immediately. It was the first time that explosives strapped to a robot had been used in American domestic law enforcement. Although its arm sustained damage in the blast, the robot was still functional.
https://en.wikipedia.org/wiki/2016_shooting_of_Dallas_police...