A Texas Rangers report on evidence from the Branch Davidian siege raises questions about shell casings found at the scene of the 1993 tragedy.

The report sent Friday to Congress indicates that the Rangers recovered a dozen .308-caliber sniper rifle shell casings and 24 Israeli-made .223-caliber casings from a house used by the FBI's hostage rescue team throughout the 51-day siege. The house is the same one from which an FBI agent reported hearing shots fired on the final day of the Branch Davidian standoff.

The agent has since said that account was wrong, and FBI officials insist that none of their agents fired a single shot during the standoff. Bureau officials have noted that the shell casings could have come from agents of the federal Bureau of Alcohol, Tobacco and Firearms, who used the house as a sniper post and shot repeatedly at the Branch Davidian compound as they tried to search it on Feb. 28, 1993.

The Rangers report offers no conclusions about the potential significance of the sniper rounds or other evidence under scrutiny.

But law enforcement officials in Texas said the report presents compelling questions for both Congress and former senator John C. Danforth, the special investigator appointed last week by Attorney General Janet Reno to reexamine the Waco case.

"We now have ballistics exams that can take a shell casing and determine exactly what gun it was fired from," said one official in Texas who declined to be identified.

In the report, a Texas Rangers sergeant assigned to sort through the Branch Davidian evidence kept by the Texas Department of Public Safety (DPS) wrote that his efforts were slowed by the lack of a complete set of crime scene photographs from the case.

"It is my understanding that the FBI had taken all of the 35-mm film, negatives and reference material into their possession, and only a limited number of photographs were returned to the Texas Department of Public Safety," Ranger Sgt. Joey Gordon wrote in the report.

The inch-thick document, subpoenaed earlier this month by the House Committee on Government Reform, indicates that the DPS has preserved other problematic evidence, including a spent military flare, DPS photographs and videos and "flash-bang" grenades, which emit a loud concussive noise and a blinding flash and are used by police to stun or distract suspects.