Friday night, authorities named a person of interest in the case, the ex-husband of the victim, Melissa Bridgewater, 45.
At the time, police said they just want to question him.
Witnesses say the gunman was apparently waiting for Bridgewater outside the hotel, and when she left, he shot her.
Police say the victim was leaving the Doubletree Hotel in Oakbrook about 6 a.m. Friday, after attending a New Year's Eve party the night before. She was backing up her car when the gunman approached and fired at her head. Her family believes she knew her killer.
"I'm sure she did, and hopefully justice will be served," said Lavar Bridgewater, her son.
Bridgewater lived in Bolingbrook. She was recently divorced.
Late Friday evening, police released a photo of Jerry Hudson, 48, her ex-husband, who they describe as a person on interest. They say he had recently made threatening statements to Bridgewater. Family members say Bridgewater had just begun dating someone else and had a bright outlook for the new year.
"She had goals, and she had set goals that she was going to win in 2010. She was just going to move on with her life, and what was in her past was in her past," said Bridgewater's sister, Patricia Farrell.
"She just had that zest. The sense of her presence made you smile," said her friend, Dorothy Thomas.
Family and friends say Bridgewater never indicated she was having problems with anyone. They say she was excited about the New Year's Eve party she was attending at the hotel.
"It's very shocking. It's very sad," said neighbor Pam Eulbert.
Family members admit they have their ideas about the suspect, and they say they have shared that information with police.
"If you're out there, and you are hearing this, come forth. You can't run from this," Lavar Bridgewater said.
Bridgewater worked in the office of a suburban cardiologist. One co-worker says she was so excited about the party, she brought several dresses into work yesterday so they could help her choose what to wear.
Police are collecting whatever video they can find from the hotel and other nearby businesses, even cameras on the Tollway nearby.