The police have new measures at their disposal to catch bank robbers, such as well-armed SWAT teams. Forensic identification techniques have also improved greatly; should a bank robber fire a gun, the police can trace the bullet to the exact firearm using ballistic fingerprinting. Martin Kemp, in a BBC documentary, once inquired on the effectiveness of an Uzi in a bank robbery, to which the firearms training instructor joked "that would be sixty-four pieces of evidence to convict you." The sawed-off shotgun, a common robbery weapon in the United Kingdom, Australia and New Zealand where handguns are difficult to obtain, is easily concealable but not particularly effective.