Shannon Vincel, 46, was beaten to death as she sat outside her hotel room, WLS-TV reports. The killing seemed random, and police are still scrambling to find a suspect or a motive in her death.

After surviving chemotherapy and a double mastectomy, she was looking forward to getting her life back.

Vincel, who lived in Springfield, Missouri, had traveled to Zion, Illinois to be treated at the Cancer Treatment Center of America, a trip she made every two weeks. According to KSDK-TV, she was waiting for a shuttle bus to take her to a nearby treatment center late Monday night alongside another patient. Then, all of a sudden, a man dressed in dark clothing approached, started hitting Vincel on the head with an unknown object, and then ran off, the Associated Press reports. She was taken to the hospital with a severe head injury, and her family took her off life support.

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 Her family said it was not a robbery, and police reportedly do not have any leads. The Cancer Treatment Centers of America is offering a $25,000 reward for information leading to the arrest of the person responsible for her death. They also released the following statement:

“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. Our number one priority remains the safety and wellbeing of our patients, guests and employees.”

If you would like to help, the  family is asking for donations to the Opera Theatre of St. Louis or Stray Rescue in St. Louis. If you have any information about the killing, you’re encouraged to call police at (847) 872-8000 or Lake County Crime Stoppers at (847) 662-2222.