Branch Davidian leader David Koresh and about 80 followers died in the 1993 inferno at the compound 10 miles east of Waco, Texas. Authorities have denied using any incendiary devices during the assault that ended when the compound was consumed by fire.
Investigators concluded that sect members set the fire.
A probe by the Texas Rangers became the backbone of a 1994 criminal trial in which eight Branch Davidians were convicted of charges ranging from manslaughter to weapons violations. More than 12 tons of evidence were gathered and much of it is stored in Waco.
A researcher for a 1997 documentary critical of the government's conduct was allowed access to the evidence last spring, the Morning News reported.
The researcher, Michael McNulty, who is preparing a new documentary on the standoff, said he found that at least six items listed in Texas Ranger inventories as silencers or suppressors were actually Â"flash-bangÂ" devices, commonly used by law enforcement to stun suspects.
McNulty said the devices sometimes ignite fires in enclosed spaces because they emit a loud bang and flash driven by a small pyrotechnic charge.
Texas Rangers' evidence logs indicate the devices were found in areas of the Davidian compound in which the fires broke out, McNulty said.
Â"It's our belief that these pieces of ordnance could and probably did have an impact on the fire on April 19th,Â" he told the Morning News.
Justice Department spokesman Myron Marlin called the conclusion Â"nonsense.Â"
Â"We know of no evidence to support that any incendiary device was fired into the compound on April 19, 1993,Â" Marlin said.
The Davidians and authorities became locked in a 51-day standoff after agents of the Bureau of Alcohol, Tobacco and Firearms were fired upon when they tried to arrest Koresh on Feb. 28, 1993.
The compound erupted in flames April 19 when federal agents punched through the walls and fired tear gas inside.
Congressional hearings have pointed to mistakes by the law enforcement officers, but none has been charged with a crime. A lawsuit filed by surviving Davidians and the relatives of the dead challenges the conclusion that the Davidians started the fire and also shot first during the raid.