BELOIT, Wis. -- Beloit police are asking for the public's help in identifying a person or persons of interest in the slaying of a woman in downtown earlier this week.

Authorities released a pair of sketches that are likeness of a person or persons who were apparently in the downtown area on Monday morning when Julienne McGuire was killed in the Edward Jones office building where she worked.

McGuire, 44, of Janesville was found dead after she opened the office at about 8 a.m. A co-worker found her dead around 9:30 a.m., WISC-TV reported.

Police aren't describing the person or persons as suspects, but said that they might be witnesses.

Norm Jacobs, the deputy police chief, said that they hope the sketches will yield new leads.

"We're hoping that by presenting this through the media, that someone will recognize who they are and give us a name," Jacobs said.

Police said that they don't know if the sketches represent two people or one who could be a combination of the two sketches.

Investigators haven't released any information about how McGuire died, WISC-TV reported.

On Tuesday, police confirmed that they had questioned McGuire's ex-boyfriend, but investigators said that they aren't calling him a suspect. They did say that McGuire had a restraining order issued last year against him and the man was questioned in the presence of his attorney.

The killing is the city's second murder of the year.

Anyone with information is asked to call Beloit police at (608) 364-6800.