WASHINGTON — An internal investigation into the ill-fated raid on a religious cult near Waco will focus largely on why the Bureau of Alcohol, Tobacco and Firearms went ahead with the raid, despite learning that cult members knew of their plan, officials said Monday.

In addition, Treasury Department officials said they want to know whether ATF failed to take advantage of opportunities to arrest cult leader Vernon Howell, also known as David Koresh, when he was away from the group’s heavily armed compound.

Treasury Secretary Lloyd Bentsen said he expected the investigation to take about four months.

The Feb. 28 effort to serve arrest and search warrants on Howell and his Branch Davidian followers erupted in a bloody gun battle that left four ATF agents and an unknown number of cult members dead.

That led to a protracted standoff between the cult and members of the FBI’s hostage rescue team and the final fire in which Howell and most of his followers died.

Bentsen said his agency’s investigation will deal exclusively with circumstances leading up to the original ATF raid and not with FBI handling of the standoff.

“We want an impartial, comprehensive and uncompromising inquiry, and we want to let the American people know what happened and why,” he said.

He denied that “anyone at the Treasury Department” was thinking of recommending that ATF functions be transferred into another agency, such as the FBI.

The probe will be conducted by investigators from sister agencies in the Treasury Department, the Secret Service, the Customs Bureau and the Internal Revenue Service, said Assistant Treasury Secretary Ronald Noble.

It will be overseen by a panel of outside experts: Former newspaper reporter and editor Ed Guthman, Los Angeles Police Chief Willie Williams and attorney Henry Ruth, chief Watergate prosecutor in the 1970s.

H. Geoffrey Moulton, an attorney and former clerk to Justice William Rehnquist, will direct the probe.

The outside experts are apparently intended to provide the public with assurance that the investigation is thorough and open.

Noble said primary concerns will be what ATF supervisors knew and when they knew it.

“A major question that is foremost in our minds is, given that the element of surprise was lost, he made the decision to go forward,” he said. “The plan turned on the element of surprise.”

Noble said the internal review also would examine reports that Howell was frequently away from the Branch Davidian compound and might have been arrested without serious resistance.

Read the Tribune-Herald's 7-part investigative series on the inner workings of the Branch Davidians. Hours after Part 2 appeared in print, the ATF raided the group's compound.

Read the Tribune-Herald’s account of the ATF raid on the Branch Davidian compound on Feb. 28, 1993. Four ATF agents and six in the compound were killed in the gunfight.

Read the daily news accounts of the 51-day siege at the Branch Davidian compound near Elk, which began Feb. 28 and lasted until April.

April 19 and beyond: FBI agents began inserting canisters of tear gas into the Branch Davidian compound in the early morning hours. By noon, it was on fire.

Federal officials left the compound site in late May 1993. As identifications of bodies continued, questions about the survivors, the compound and the cult itself began to emerge.

As the world began to take a critical look back at the events and legal proceedings continue, the ATF's bombshell report forces a shakeup at the top after the raid gone "tragically wrong."

In 1994, the surviving Davidians went on trial in San Antonio. Over six weeks, more than 140 witnesses testified, with the verdict coming just two days prior to the anniversary of the ATF raid.

The Rodenville shootout and the 1988 trial, the end of the world in 1959 and more stories from deep in the Trib archives.