As the woman calmly stood at the checkout counter in Washington County, signing a receipt from a stolen credit card, she seemed oblivious to a security camera recording her actions for all the world to see. Ditto for a tattooed service station robber in St. Paul, two men involved in a Richfield pawn shop robbery and murder, and two suspected Robbinsdale home invaders.

In each case, crystal-clear surveillance images led to arrests.

Stunning advancements in video surveillance technology -- it's the new DNA of crime fighting, one Minneapolis business owner said -- have police crowing about the ease and speed of catching suspects accused of robbery, theft, assault and other crimes. While authorities say that it's difficult to measure how much new high-resolution images contribute to successful prosecutions, personal stories about speedy identifications of suspects abound.

Police received dozens of calls after photos of Dawn Marie Rassett, the woman charged in Washington County with stealing credit cards from teachers' purses, were published. And additional charges came last week in Ramsey County after police found more video allegedly showing Rassett, also known as Dawn Marie Scott, using stolen credit cards at businesses in Roseville, White Bear Lake, Maplewood, Vadnais Heights and North St. Paul.

Rassett, 41, of Maplewood, remains in the Washington County jail, accused in a rash of thefts from schools, churches, a doctor's office and even a wedding.

"The quality of the still frames we got from the videos at the convenience stores is the main reason we caught her," said Sgt. Andy Ellickson, an investigator at the Washington County Sheriff's Office.

The digital technology allows crisp quality and timely clues that videotapes never did, often heading off courtroom arguments over fuzzy images that might not make it clear who committed the crime.

"The cameras have just gotten better. They're like nice portraits," said Dave Hautman, general manager of Franklin Nicollet Liquor in the Uptown neighborhood of Minneapolis. "It makes everybody feel more comfortable, more safe, including the customers."

The liquor store bought its cameras from Video Surveillance Solutions, an Iowa firm with Minnesota offices in Roseville. The company's Minnesota product manager, Todd Rubey, said video surveillance in the metro area has increased about 300 percent since 2002.

Computer-driven digital cameras also have applications for residences, ambulances, city parks, summer cabins, horse barns and even farmers who can monitor machinery and crops. Front-pocket surveillance units, barely larger than a pen, sell for $209, he said.

Nearly 80 percent of all metro business owners now have cameras installed, Rubey said, because employees steal much more from businesses than shoplifters or robbers do. Cameras, which start about $2,000 plus labor for installation, "hold accountability to a higher standard," he said.

For most business owners, the process of putting fresh tapes into a VCR has gone the way of eight-track music tapes. Business owners now can record images for months. If they're robbed, a few clicks on the computer will take them to the precise time of the holdup to help police catch a suspect. Such was the case in Woodbury on Thursday when police released a photo of a suspect using stolen credit card numbers on fake cards he had created.

Concerns about privacy

To other people, the spread of surveillance cameras smacks of George Orwell's "1984," said Chuck Samuelson, executive director of the American Civil Liberties Union of Minnesota. The novel described a society of pervasive government surveillance, public mind control and the voiding of citizens' rights. Many Minnesotans don't like having their every move subject to scrutiny and preservation, he said.

Another worrisome consequence of the increasing surveillance, Samuelson said, is that police tend to control many of the videos that show confrontations and might hide evidence of their own misconduct.

Rubey, a former Air Force engineer, said he understands the privacy concerns. But new surveillance technology, he said, makes it harder than ever for misbehaving cops to disguise excessive force, just as it's difficult for suspects who rob banks or use stolen credit cards to argue their guilt.

Doubt over murky images,

"There's no question but that technology is better, we're getting better pictures," said Doug Johnson, Washington County's chief attorney. But he also said that nobody in his office could remember a time when a prosecution failed because of a grainy surveillance photo.

Although images now show everything from assaults on store clerks to police brutality and car break-ins, surveillance cameras a decade ago recorded murky images that left doubt.

In 1999, authorities tried to determine who abducted Katie Poirier, a Moose Lake convenience store clerk. Although Donald Blom was eventually convicted of her kidnapping and murder, his daughter and some of his co-workers said during his trial that they didn't recognize the person in the video who was pushing Poirier out the door.

"In today's world I think we would have more and better images of Blom," said Dave Bjerga, assistant superintendent of Minnesota's Bureau of Criminal Apprehension. "It wouldn't have taken as long to track him down."

Hautman, who also works at the affiliated Red Lion Liquor in Burnsville, said he hoped the nine cameras pointed at the front door and elsewhere of the Franklin Nicollet store would make robbers think twice. He can monitor from home or anywhere else with a laptop computer what the cameras see. Changes in technology, he said, are astounding.

"When banks got robbed you had these rotten pictures," he said of the old VHS tapes. "Now it's like having an 8-by-10 glossy."

Kevin Giles • 612-673-4432