An employee at an upscale Maryland yoga clothing shop is accused of killing a co-worker who found suspected stolen merchandise in her bag, then trying to conceal the crime by tying herself up and blaming the attack on two masked men.

Brittany Norwood was ordered held without bond Monday on a charge of first-degree murder after Montgomery County State's Attorney John McCarthy described the slaying.

McCarthy said Norwood, 28, spun an elaborate ruse to convince authorities that she and the dead woman, Jayna Murray, had been attacked inside the Lululemon Athletica shop in Bethesda where they worked.

"Her cunning and her ability to lie is almost unparalleled," McCarthy said of Norwood.

When Norwood was found the morning of March 12 inside the shop, she told police that she and Murray, 30, had been sexually assaulted by two masked men who came in the previous night after closing time. Norwood was found with minor scratches and other wounds, her hands and feet bound.

Police initially treated Norwood as a rape victim, offering rewards for information leading to arrests and even doing surveillance on a person of interest. But detectives concluded that neither woman had been sexually assaulted and that Norwood had staged the scene. She was arrested Friday and charged with murder and faces life in prison if convicted.

Norwood's blood was found inside Murray's car, McCarthy said. Only two sets of bloody footprints were found inside the shop, and workers at the adjacent Apple store reported hearing two women _ but no men _ arguing when the attack was believed to have happened. And Norwood's wounds were self-inflicted, authorities said.

"No one could have ever anticipated seven or eight days ago that we would be standing here telling you what we are telling you today," McCarthy told the judge.

Norwood appeared via videoconference from the jail where she is being held. She did not speak during the brief hearing except to answer procedural questions, and her public defender declined to comment as he left court.

McCarthy offered new details about what happened before Murray died, saying she had been asked by a store manager to check Norwood's bag for stolen merchandise. Murray called the manager that night to say she believed Norwood had been stealing.

That same night, after the store had closed, Norwood told Murray she needed to get back into the store because she left her wallet. When the two returned, they argued over the suspected theft, McCarthy said.

Norwood then picked up some sort of weapon inside the store and used it to beat Murray for as long as 20 minutes throughout the shop, McCarthy said. He said Murray sustained a severed spinal cord and blows "too numerous to count."

"The nature of this crime is shocking in terms of the level of violence that was directed at the victim," McCarthy said.

He said Norwood tracked Murray's blood through the store while wearing a size-14 shoe, used by the store in determining the length of pants, to throw off detectives.

McCarthy said detectives confronted Norwood and her family on Friday with what they believed happened. He said the family asked to be left alone with Norwood, who could then be heard telling a relative that she was sorry and didn't want to disappoint him. But she also told him she was wary of talking more because she feared they were being recorded, McCarthy said.

Norwood was most recently living in Washington, D.C., but grew up in Washington state and was a standout soccer player for Stony Brook University in New York. The soccer coach there did not return phone messages on Monday.

Appearing Monday on ABC's "Good Morning America," Murray's parents said only that they believe in the justice system and that they will let the case work its course.

The Lululemon shop remained locked Monday morning, with strips of yellow police tape still attached to the door and its windows covered from view by large pieces of brown paper. Businesses along the street displayed white ribbons in Murray's memory.

The killing stunned residents and workers in Bethesda, an affluent suburb northwest of Washington where violent crime is rare. Some people said Murray's death gave them a heightened sense of their surroundings and made them think twice about walking outside late at night. On Monday, some in the area said they were somewhat relieved to know that there weren't two killers on the loose as first thought.

Jill Kolakowski, 36, of nearby Chevy Chase, said she's been inside Lululemon and even thought Norwood looked familiar when she saw her on the news. The killing was striking because it seemed so random, she said.

"How much of a relief is it really when it could be a woman who babysat your children or a woman who sold you workout clothing?" Kolakowski asked.