MADISON, Wis. -- Those close to a woman found dead Wednesday in her West Doty Street apartment said she was a very ambitious college student with some very big goals.

Brittany Zimmermann, 21, was on track to graduate ahead of schedule in the spring of 2009 with a degree in medical microbiology and immunology from the University of Wisconsin-Madison.

Those close to her said she wanted to pursue a master's degree and doctorate in infectious disease. UW-Madison officials are remembering Zimmermann as a driven student who had a bright career in front of her in the field of public health.

She worked for the last three years at a part-time job in the UW-Madison Registrar's Office. Her co-workers there said they are stunned by her death.

"She was the kind of person that even if you didn't know her, she would brighten up your day because she always had this smile on her face," said Joanne Berg, UW-Madison registrar. "She really was just an incredible woman. She was working really hard to get through school quickly."

Berg said employees in the office have been informed about assistance programs and that some of the students who worked there have already set up group sessions with the Dean of Students Office to talk about Zimmermann and any fears they have.

Zimmermann was a graduate of Marshfield High School. Her former guidance counselor said Zimmermann was about to marry the boyfriend with whom she was living in Madison.

"She just had so much hope. She was going to bring so much to so many people. To hear that she was tragically murdered today was just a shock for all of us here," said Liz Dostal, assistant principal at Marshfield High School.

The slaying has frightened some students and downtown Madison residents. It is the third unsolved killing in the campus area in less than one year.

UW-Madison officials are planning a vigil for Zimmermann on Sunday.