Rush University Medical's Cris Lowry immediately knew something was wrong when she received a phone call Sunday night informing her that Virgie Perillo, 73, had failed to show for her overnight shift.
Perillo has worked there as a registered nurse for the past 40 years.
"For years she never called in (sick). She was that dedicated. She would come in no matter what," said Lowry, Perillo's supervisor at Rush.
About 9:20 p.m Saturday night, a neighbor driving by Perillo's house at 33rd and Parnell found her garage open and her body on the ground unresponsive. Police say she was brutally beaten -- her face smashed.
Neighbors tell NBC Chicago that detectives scoured alleys nearby looking for the murder weapon, which they believe to be either a metal pipe or a baseball bat.
Law enforcement sources with knowledge of the investigation tell NBC Chicago that robbery appears to be the motive, and that Perillo's cell phone was missing along with some garden tools from the garage.
"It appears that she sustained such substantive head trauma, that it would indicate there was an attack," said Officer John Mirabelli, Chicago Police Media Affairs.
The victim's son, John Perillo, is at a loss to understand why it happened.
"Why? For what practical reason could they kill my mom?" Perillo said. "She's never hurt a fly so I really don't know why this has happened to her."
Concern led to questions Monday in Perillo's close-knit Bridgeport neighborhood.
"Good God, It's not suppose to happen around here. It's suppose to be a nice neighborhood," neighbor Larry Menaker said.
A recent armed hold-up on Parnell -- not far from Perillo's house -- led to a community forum, where Chicago Police met with residents.
Police say it's too early to say whether that crime is connected to Perillo's murder.
But Perillo's boss says her friend of 40 years will be missed at Rush.
"She just wanted to make patients feel cared for. If it was rubbing your back or holding your hand. She just had the compassion to do whatever it took to make that individual feel like they were her own family member," Lowry said.