VANCOUVER What prompted three teenaged girls to don masks, carry a sawed-off shotgun and rob a local 7-Eleven store this week?

It may have been the Dixie Chicks.

As veteran police officers shook their heads over details normally associated with hardened male criminals, youth crime expert Raymond Carrado said the level of violence among teenagers, particularly girls, is on the increase. Given cultural trends, no one should be surprised, said Mr. Carrado, a criminologist at Simon Fraser University. "Although girls engaged in crime is still an aberration, the rate has gone up dramatically. It's simplistic and naive to think we are not going to see incidents like this."

Mr. Carrado said girls with troubled backgrounds are often influenced by images of toughness increasingly provided in today's movies and the media. "You get that whole defiant Madonna look, and look at that song by the Dixie Chicks. It may sound funny, but when you get 100,000 girls listening to it, don't think there are not 10 unstable ones who are not going to react." Mr. Carrado was referring to the country trio's hit song Goodbye, Earl, which recounts a revenge poisoning of an abusive husband.

"This kind of youth violence didn't go on in the 1960s. Who had heard of swarming then? Today, as we know, this kind of youth crime can occur anywhere."

RCMP Constable Peter Thiessen said he had never heard of a similar incident involving such young girls in 20 years as a police officer. "When you see 14- and 15-year-old girls going in and pointing a sawed-off shotgun right in the face of a clerk, ... I think everyone should be concerned," Constable Thiessen said. "We're talking about kids here, and girls to boot."

The gun-toting girls made off with only a small amount of cash and cigarettes. Three suspects were arrested, along with another teenaged girl and a 22-year old man, after a stolen vehicle crashed and tipped over while being pursued by police. The gun used in the robbery was described by police as a sawed-off Remington model .870 magnum.

The three young suspects, who cannot be named because of their age, have been charged with robbery and committing a crime using a disguise. A bail hearing yesterday was adjourned until Jan. 24.