Robbery victim Dorothy Ann Barr took the witness stand in Montgomery County Circuit Court yesterday and identified Timothy Joseph Buzbee as the man who grabbed her from behind and wrested a paper bag from her hand on a dark residential street more than two years ago.

Barr's testimony opened the second day of Buzbee's trial on the robbery charge before Circuit Court Judge Irma S. Raker. Buzbee is also scheduled to stand trial in the coming months on charges of raping five women in what have become known in the county as the Aspen Hill rapes. The 25-year-old land surveyor, who grew up in the county and now lives in Frederick, has pleaded not guilty to all of the crimes.

Buzbee's defense attorneys have asserted that when Buzbee was stopped the night of the robbery, Dec. 9, 1980, it was a case of "mistaken identity" and that he was not dressed in the type of clothes Barr has testified her assailant wore. Buzbee was not arrested that night, but the investigation was renewed last fall after police had begun to look at Buzbee as a suspect in the Aspen Hill rape cases.

Yesterday, the prosecution also called to the stand James Bowers, one of the two men who chased Barr's attacker after they heard her screaming in the street in front of one of their homes. Bowers testified that they lost sight ofthe attacker after he ran down a "pitch black" path that runs between St. Lawrence Drive, where the attack occurred, and Williamsburg Drive, in the Four Corners area.

A few minutes later on Williamsburg, according to Bowers, Buzbee "trotted up to" him, dressed in short shirt sleeves on that December night, asked him what was going on and asserted that he had been out jogging.

"I looked at his attire, and I said 'Strange clothes to be jogging in,'" Bowers testified. Then, Bowers said, he put his hand on Buzbee's shoulder and chest, felt his heart pounding and decided to detain him.

Bowers, questioned by Assistant State's Attorney Barry Hamilton, testified that the man he had chased down the path and Buzbee "look to be the same." But under cross-examination by defense attorney Reginald W. Robbery, Bowers acknowledged that he could not really see the man he was chasing and that when asked to describe the man previously he was only able to say that it was a white male.

In her testimony yesterday, Barr said that the man who grabbed her from behind and fled with the paper bag containing a coffee mug and about $7 was dressed in a green Army fatigue jacket, dark pants and heavy cotton gloves. She said she looked "very quickly" at his face as they struggled.

She testified that when police took her to Williamsburg Drive, and asked her to look at the man stopped by Bowers, she noted he was not wearing a jacket or gloves. "I told police I thought it was him . . . the man who jumped me," Barr testified.

Under cross-examination she testified that she also told police that "two of the utmost identifying things were the gloves and jacket and they weren't there."

Barr also testified that as she sat in the police car that night she realized she knew the man she had identified as her attacker. She told a detective that she believed the man was Timothy Buzbee, who several years before had dated a close friend. Barr testified that police confirmed that the man they had detained was indeed Buzbee.