ZION, Ill– The Zion Police Department  is still searching for a suspect who brutally attacked a Springfield woman sitting outside the cancer treatment center Monday night.

A Zion Police Department spokesperson told KOLR10 News there is no suspect in custody and there is no person of interest currently but the investigation is continuing.

So far, the only description of a suspect police have given is a black male wearing dark colored clothes.

The suspect approached 46-year-old  Shannon Vincel on the sidewalk while she was sitting outside of The Cancer Treatment Centers of America-Zion while sitting on a bench and struck her in the head with an unknown object, police said. She was taken to Condell Medical Center in Libertyville with life-threatening injuries.

Family members say she was pronounced brain-dead when she arrived at the hospital Monday.

She died from those injuries Tuesday night around 10:30 p.m.

Fabienne Vincel, Shannon’s sister, told KOLR10 News Shannon was flying back and forth every two weeks to the get radiation treatment for breast cancer.

She said Shannon was “happy-go-lucky and the sweetest thing.”

“You never expect someone you know to be murdered, it’s outrageous.”

The family made the decision to disconnect Shannon from life-support Tuesday night.

Cancer Treatment Centers of America spokeswoman Kristen Gerlach said, “Our thoughts and prayers go out to the family and friends of the victim involved in the tragic incident outside of Guest Quarters West, one of our hotel accommodations located at 1911 27th Street, Zion, Ill. We continue to support the ongoing investigation of the Zion Police Department in support of the Lake County Major Crimes Task Force.”

Cancer Treatment Centers of America (CTCA) has pledged $25,000 for information leading to the arrest and conviction of the individual(s) responsible for the murder of Vincel.

“We knew her about two weeks, and she was a real nice girl,” said one man, who was providing care to his brother receiving treatment.

Other patients placed two small flowers on the ground a the scene of the attack.

The Lake County Major Crime Task Force, along with the Zion Police Department, are now investigating this incident as a homicide.

Vincel is originally from St. Louis and went to Drury University. She is survived by her two sisters and mother.

No funeral arrangements have been made yet.

(Sun-Times Media Wire, Chicago Sun-Times, CBS Chicago contributed to this report)