Ruth George was walking to her car in a Chicago parking garage late at night when a man called out to her. After she ignored him, police say he followed her into the garage — and the story has a tragic ending.

The body of the 19-year-old college student was found in a University of Illinois at Chicago parking garage over the weekend. The Cook County medical examiner said George died of strangulation, the university said in a statement.

Donald Thurman, 26, who lives near the school, was charged Monday with first-degree murder and sexual assault. Police said he was released from an Illinois prison in December 2018 after serving two years of a six-year sentence for armed robbery.

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George's family first contacted police on Saturday after not hearing from her since the night before. After tracking her phone, UIC police found her unresponsive in the back seat of her family's vehicle.

Ruth George via Facebook

Police reviewed surveillance footage and said Thurman could be seen walking behind George, following her down the block and into the parking garage at around 1:35 a.m. Saturday.

Detectives tracked his travel patterns, found Thurman near a Blue Line train station and took him into custody. They said he gave a full confession Sunday.

Thurman has no connection to the university or to the victim, UIC police said.

CBS Chicago reports that during a hearing on Tuesday, Assistant State's Attorney James Murphy said Thurman grew angry that George was ignoring his catcalls and followed her into the garage.

"The defendant thought she was pretty and tried talking to her," Murphy said. "But the victim ignored him."

Donald Thurman UIC Police via AP

"The defendant followed the victim and tried to talk to her again, and then the defendant cat-called at her.

"When the victim arrived at her car, the defendant was angry that he was being ignored," Murphy said. "The defendant came up behind the victim grabbed her around the neck from behind and put her in a chokehold."

George was an honors student studying kinesiology. On Monday, more than 200 UIC students returned to the parking garage to light candles and lay flowers, CBS Chicago reports.

"She was an incredible student and an incredible person," Tyler Nielsen, a coordinator in the honors college, said. "It's a tragedy tenfold. She was such a vibrant part of the community. You can feel that pain already."

"It is very difficult to find words that can express the sadness our entire community experiences today following the news of the tragic death of a 19-year-old undergraduate student," said UIC Chancellor Michael Amiridis. "We offer our sincere condolences to the student's family and friends and I know that all of us have them in our hearts as they struggle with this devastating loss."