At Mount Carmel in Waco, Texas, agents of the U.S. Treasury Department’s Bureau of Alcohol, Tobacco, and Firearms (ATF) launch a raid against the Branch Davidian compound as part of an investigation into illegal possession of firearms and explosives by the Christian cult.

As the agents attempted to penetrate the complex, gunfire erupted, beginning an extended gun battle that left four ATF agents dead and 15 wounded. Six Branch Davidians were fatally wounded, and several more were injured, including David Koresh, the cult’s founder and leader. After 45 minutes of shooting, the ATF agents withdrew, and a ceasefire was negotiated over the telephone. The operation, which involved more than 100 ATF agents, was the one of the largest ever mounted by the bureau and resulted in the highest casualties of any ATF operation.

David Koresh was born Vernon Wayne Howell in Houston, Texas, in 1959. In 1981, he joined the Branch Davidians, a sect of the Seventh Day Adventist Church founded in 1934 by a Bulgarian immigrant named Victor Houteff. Koresh, who possessed an exhaustive knowledge of the Bible, rapidly rose in the hierarchy of the small religious community, eventually entering into a power struggle with the Davidians’ leader, George Roden.

For a short time, Koresh retreated with his followers to eastern Texas, but in late 1987 he returned to Mount Carmel with seven armed followers and raided the compound, severely wounding Roden. Koresh went on trial for attempted murder, but the charge was dropped after his case was declared a mistrial. By 1990, he was the leader of the Branch Davidians and legally changed his name to David Koresh, with David representing his status as head of the biblical House of David, and Koresh standing for the Hebrew name for Cyrus, the Persian king who allowed the Jews held captive in Babylon to return to Israel.

Koresh took several wives at Mount Carmel and fathered at least 12 children from these women, several of whom were as young as 12 or 13 when they became pregnant. There is also evidence that Koresh may have harshly disciplined some of the 100 or so Branch Davidians living inside the compound, particularly his children. A central aspect of Koresh’s religious teachings was his assertion that the apocalyptic events predicted in the Bible’s book of Revelation were imminent, making it necessary, he asserted, for the Davidians to stockpile weapons and explosives in preparation.

Following the unsuccessful ATF raid, the Federal Bureau of Investigation (FBI) took over the situation. A standoff with the Branch Davidians stretched into seven weeks, and little progress was made in the telephone negotiations as the Davidians had stockpiled years of food and other necessities before the raid.

On April 18, U.S. Attorney General Janet Reno approved a tear-gas assault on the compound, and at approximately 6:00 a.m. on April 19 the Branch Davidians were informed of the imminent attack and asked to surrender, which they did not. A few minutes later, two FBI combat vehicles began inserting gas into the building and were joined by Bradley tanks, which fired tear-gas canisters through the compound’s windows. The Branch Davidians, many with gas masks on, refused to evacuate, and by 11:40 a.m. the last of some 100 tear-gas canisters was fired into the compound. Just after noon, a fire erupted at one or more locations on the compound, and minutes later nine Davidians fled the rapidly spreading blaze. Gunfire was reported but ceased as the compound was completely engulfed by the flames.

Koresh and at least 80 of his followers, including 22 children, died during the federal government’s second disastrous assault on Mount Carmel. The FBI and Justice Department maintained there was conclusive evidence that the Branch Davidian members ignited the fire, citing an eyewitness account and various forensic data. Of the gunfire reported during the fire, the government argued that the Davidians were either killing each other as part of a suicide pact or were killing dissenters who attempted to escape the Koresh-ordered suicide by fire. Most of the surviving Branch Davidians contested this official position, as do some critics in the press and elsewhere, whose charges against the ATF and FBI’s handling of the Waco standoff ranged from incompetence to premeditated murder. In 1999, the FBI admitted that they used tear-gas grenades in the assault, which have been known to cause fires because of their incendiary properties.