Earlier this month, US Postal Service letter carrier Kierra Coles left her Chicago apartment apparently dressed for work.
A neighbor's surveillance video captured her walking past her vehicle in her work uniform, CNN affiliate WLS reported.
Coles was last seen on October 2, Chicago police said. She is three months pregnant, WLS reported.
Chicago police said in a statement they "suspect possible foul play" in the 27-year-old's disappearance because she has been missing for more than two weeks. The reward for information leading to Coles' whereabouts is now more than $28,000.
"I miss the smile on her face. If anybody knows anything, please, call in. Let us know," her father Joseph Coles, who traveled from his home in Racine, Wisconsin to help in the search, told WLS.
Coles was last seen near East 82nd Street and South Coles Avenue, according to Chicago police. That location is about 3 miles away from where WLS reported Coles lives.
Her family did not hear from her and filed a missing person's report on October 4, WLS reported.
Coles' family said it's unlike her to just disappear.
"We talk all the time. If we miss one day, it's just one day," Coles' mother, Karen Phillips, told WLS. "Never, four, five, six, seven, eight, nine days. Never."
Phillips said she wants to be able say that her daughter just went somewhere and didn't want to tell anyone.
"But I don't feel that," Philips said.
The US Postal Inspection Service, the law enforcement arm of the US Postal Service, offered a $25,000 reward this week for information that could help find Coles.
Coles' union, the National Association of Letter Carriers, added another $3,500 to the reward pool. That includes a $1,000 contribution from community activists, Mack Julion, president of the union's Chicago branch told HLN, CNN's sister station.
"We're going to find our sister," Julion said.
Coles stands 5-feet 4-inches tall, weighs about 125 pounds and has brown eyes and black hair, Chicago police said. She has a tattoo of a heart on her right hand and another that says "Lucky Libra" on her back.