General intro to the Waco tragedy
The events outside Waco unfolded in 1993, at a point when the Clinton Administration was new in office. BATF was facing some pressures -- an initiative to reinvent government by phasing out inefficient agencies was on the table, and the agency looked like a target for that.
What was needed was a big action, one that would bring in lots of favorable publicity and also curry favor with the Clinton White House. There was talk of trying to ban "assault rifles," so those seemed a good target. The agency got wind of a religious group generally called Davidians (they themselves didn't use that term), located in a big building called Mt. Carmel, in a rural area NE of Waco, Texas. The Davidians were headed by a David Koresh, who was said to have a fondness for underage women. BATF also discovered that the Davidians had bought a lot of AR-15s. All were purchased via legal purchases from an FFL. ATF ginned up a search warrant affidavit that claimed (1) a person had heard full auto fire in the vicinity of Mt. Carmel, but Koresh and a few other Davidians who could be checked had never registered full auto firearms and (2) a former Davidian said that they had a .50 cal, but from their description of it it was actually a .55 Boyes rifle, and thus a destructive device.
BATF threw together a SWAT team (some of its members were made members just before the raid) of 80 agents, borrowed three military helicopters, and went off to raid Mt. Carmel, on Feb. 28, 1993.
Koresh had been warned that they were coming, and when they pulled up he ran toward them, asking them to hold on and saying there were women and children inside. A shot rang out (I think it was at the rear of the building, where the helicopters were approaching) and Koresh retreated back inside. A major fire fight erupted, and Koresh was hit twice before he could get thru the door. The Davidians called 911 and eventually worked out a cease-fire: four agents and six (I think) Davidians were killed.
The powers that be decided that FBI and its Hostage Rescue Team would handle the siege of Mt. Carmel. The HRT was well supplied with military vehicles, in particular an M-1 tank, some engineering vehicles, and some Bradley armored personnel carriers. On April 19, 1993, the HRT decided to end the siege: it began firing in tear gas projectiles from the Bradleys, and spraying in massive quantities of "liquid tear gas" (CS dust dissolved in the methylene chloride) from tanks on the engineering vehicles' booms.
After some hours, the armored vehicles began to tear Mt. Carmel down, completely demolishing the "gym" at the rear and smashing into several parts of the front. A fire broke out, and driven by high winds, quickly gutted Mt. Carmel, killing 80+ Davidians, including 24 children.