"Where’s the door? I wish I knew. It stinks of a cover-up."

So said former Treasury Department official Ron Noble during a debate at NYU Law School a couple of years ago. He was referring to the steel front door of the Mount Carmel Center near Waco, Texas, home of the Branch Davidians and site of the deadliest law enforcement operation in U.S. history.

The Bureau of Alcohol, Tobacco, and Firearms, which sent 76 agents to Mount Carmel on February 28, 1993, ostensibly to execute a search warrant and arrest the group’s leader, David Koresh, on weapons charges, claimed the ensuing shootout started when the Davidians fired a fusillade through the door. But one of Koresh’s lawyers examined the door and reported that almost all of the holes puckered inward.

This crucial piece of evidence survived the fire that consumed Mount Carmel at the end of the 51-day FBI siege that followed the shootout. Then it vanished.

Noble, who oversaw the Treasury Department investigation of the BATF’s role at Waco, was not endorsing the view that the government had gotten rid of the door because it did not support the official version of events. He was simply conceding that the door’s disappearance, like the BATF’s mysteriously blank videotape of the raid, looked suspicious.

Conspiracy theories are built from details like these. And seven years after the disaster at Waco, in which more than 80 men, women, and children died, the government continues to supply them.

Interest in Waco revived last fall after The Dallas Morning News revealed that, contrary to repeated, categorical denials by Attorney General Janet Reno and other officials, the FBI had fired incendiary tear gas rounds at Mount Carmel on the last day of the siege. The FBI continued to insist that it did not start the fire, but its credibility was so damaged that Reno felt compelled to appoint a special counsel to investigate the bureau’s actions during and after the siege.

The government appears to have learned nothing from this embarrassing episode. In dealing with another important question about Waco--whether federal agents fired guns into Mount Carmel after the fire broke out--it seems intent on fostering distrust through a combination of stonewalling and unacknowledged retreat.

In a federal wrongful-death lawsuit, surviving Davidians and relatives of some who died charge that the government prevented residents of Mount Carmel from escaping the fire by shooting into the building. The FBI has always maintained that it did not fire a single shot during the siege, and in recent court papers both the Treasury Department and the Pentagon denied that personnel under their control used their weapons on the day of the fire.

The Davidians cite repeated, rhythmic flashes on infrared footage recorded by an airborne camera--flashes that several experts have identified as gunfire. The government says the flashes are probably reflections of sunlight from puddles or debris.

To help resolve this issue, the Davidians proposed a field test using a camera similar to the one the FBI had at Mount Carmel. Although the government said the camera was one of a kind, the plaintiffs managed to borrow another one from the British Royal Navy.

The FBI also said the camera was not capable of picking up gunfire--a claim rejected by infrared specialists. "I’ve personally been in a situation where I’ve seen gunfire, using the GEC-Marconi system," one told The Dallas Morning News. "In a firefight situation, it’s very, very useful to detect where the enemy is."

As a fallback position, the FBI says the camera was too far away. It also says the flashes couldn’t be from guns because the people holding them would have shown up on the tape. The Davidians argue that the shooters’ body heat could have been concealed by protective clothing.

With the field test requested by the Davidians scheduled to be carried out next month, the government is now claiming that, whatever it shows, it won’t prove anything. "It’s not impossible for this camera to detect gunfire," says U.S. Attorney Mike Bradford. "That doesn’t, in and of itself, answer the question [of whether] these particular flashes on this tape are gunfire."

Bradford has a point, but in making it he is contradicting the government’s earlier claims about the camera’s capabilities. This is the sort of shiftiness that has made it impossible to lay the lingering questions about Waco to rest.