It was a government raid that ended up with many civilian deaths including women (some pregnant) and children. The ATF and FBI were heavily armed with military equipment (Helicopters, tanks, .50 caliber sniper rifles) and it seemed to some people that they had intended to kill the Branch Davidians at Waco.

They were there to affect a warrant for weapons charges. The Branch Davidians fought to keep them at bay and a fire started on the compound. The government claimed that the cultists started the fire themselves.

Whatever you believe, 76 people died which is tremendous when you think about it. There's never really been a law enforcement raid that's been so badly botched before. It really shook a lot of people's faith in the government.