A woman has died after being attacked near a cancer treatment center in Chicago’s far north suburbs.

Shannon Vincel, of Springfield, Mo., was outside the Cancer Treatment Centers of America’s hotel facility in Zion after 9:30 p.m. Monday when she was approached by a man and hit over the head with an unknown object, police said. The attacker then ran off, according to police.

The 46-year-old was with another person on the sidewalk outside of the facility’s guest quarters in the 1900 block of 27th street, located about a mile from the hospital where patients are treated.

Vincel was rushed to Condell Medical Center in Libertyville with severe head trauma before being pronounced dead over 24 hours later, on Tuesday just after 11 p.m., according to police.

A spokesperson for the Cancer Treatment Centers of America’s Midwestern Regional Medical Center told NBC 5 that due to HIPAA privacy laws, they can not share if Vincel was a patient.

The company said it has since increased existed security as a cautionary measure and is providing onsite emotional support for patients and staff.

“Our thoughts and prayers go out to the family and friends of the victim involved in the tragic incident outside of Guest Quarters West,” the spokesperson said. “Our number one priority remains the safety and wellbeing of our patients, guests and employees.”

Police said they only have a vague description of the attacker, but signs on the property show the facility is under the watch of surveillance cameras.

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

Anyone with information regarding this case is asked to call the Zion Police Department at (847) 872-8000 or Lake County Crime Stoppers at (847) 662-2222.