Government lawyers have rejected a Texas attorney's challenge to join a scientific field test that he has said would prove that federal agents fired at the Branch Davidian compound near Waco just before it burned in 1993.
The federal lawyers sent a caustic letter Monday declining to participate in tests designed to show how airborne infrared cameras similar to those used by the FBI during the siege might have recorded the thermal signatures of gunfire.
"You and your experts are free to conduct whatever test you desire," Justice Department lawyer Marie Hagen wrote. "Although it does appear . . . that several of your assumptions about the facts, the scientists and the experts are in error and may render useless any conclusions reached, it is your choice to proceed."
Michael Caddell, a Houston lawyer representing Branch Davidians in a wrongful-death case against the federal government, said the refusal is more evidence that the government's lawyers are treating his and other efforts to determine what happened near Waco "as some sort of game."
He said the decision was particularly disturbing because outside investigators who recently began re-examining the 1993 incident have expressed interest in such a test, including House and Senate committees and the office of independent counsel John Danforth.
"Your refusal to participate in efforts to arrive at the truth of what happened . . . will clearly be interpreted by many as an admission of liability and a continuance of the government's stonewalling," Mr. Caddell wrote in response to the Justice Department.
The government has long denied that FBI agents fired at the Branch Davidian compound during the 51-day standoff. Officials have dismissed as baseless the allegations of federal gunfire on April 19. Such charges have become a cornerstone of the Branch Davidians' pending lawsuit, set for trial next May in a Waco federal court.
Leader David Koresh and more than 80 followers died in a fire that erupted on April 19, about six hours after FBI tanks began bashing the compound and spraying in tear gas. An FBI airplane circling the compound used an infrared video camera to capture the outbreak of the fire and the hours that preceded it.
In the hour before the blaze, the camera recorded repeated bursts of white flashes that appeared to come from outside the compound near government tanks and from the windows of the Branch Davidian compound.
Two experts hired by Mr. Caddell's law firm concluded that the flashes were gunfire. An infrared expert retained by House investigators reached a similar conclusion after preliminary analysis of the FBI recording.
Experts retained by the government have said they can prove that the camera was too far away to record brief bursts of heat that would have come from gunfire. They say the flashes on the tape also last too long to be gunshots.
FBI officials have refused to reveal any technical information about their camera to the media or even to Mr. Caddell's experts, citing law-enforcement secrecy issues. Experts have said that information is crucial to any accurate scientific assessment of the infrared videos.
But Mr. Caddell has said he is confident enough in his experts' conclusions that he is willing to finance a full field test, using an airborne infrared camera to record test firing from guns similar to those carried by federal agents and Branch Davidians.
In her letter Monday, Ms. Hagen took a swipe at Mr. Caddell's decision to make public his invitation for the government to participate.
"We believe that the issues should be tried [in federal district court] rather than in the press," she wrote. "We agree that this matter is of national importance and are confident that the truth will be shown at the trial."