ATLANTA -- The resident of a midtown Atlanta penthouse who was found dead in her luxury apartment late Tuesday night has been identified as a ground-breaking cancer researcher.

The victim's fiance told investigators he found the body of 57-year-old Dr. Eugenia Calle in the penthouse apartment at the Aqua Midtown building on 10th Street at West Peachtree Street.

"There did appear to be some signs of a struggle," Lt. Keith Meadows told WSB-TV Channel 2 reporter Ryan Young.

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Meadows said he believed the victim died from "blunt force trauma" to the head. She may have been dead up to 12 hours before her body was found at 11 p.m. Tuesday.

Calle was a physician and a cancer researcher, who has been the director of Analytic Epidemiology for the American Cancer Society since 1994. She was also an adjunct professor in Epidemiology at Emory University.

Calle made great contributions in the medical field, including ground-breaking research that linked cancer with obesity, according to co-workers.

Calle was engaged to be married and she and her fiance were selling her high-rise luxury apartment.

Police said somehow the killer gained entry into her apartment and killed her.

Police told Channel 2's Tom Regan they have not determined a motive for the killing.