The U.S. Postal Inspection Service is offering a $25,000 reward for information on the whereabouts of a pregnant mail carrier who has not been seen in two weeks.

Kierra Coles, 26, was last seen Oct. 2 near her home on the south side of Chicago, the Chicago Tribune reported. According to Coles' mother, she is about three months pregnant.

Karen Phillips told the Tribune she reported her daughter missing on Oct. 4 after she had heard nothing from her for two days. Coles' cellphone calls were going straight to her voicemail.

"I talk to her every day," Phillips told the Tribune. "I knew something was wrong. It's just not like her."

The distraught mother told the newspaper Tuesday that Coles’ car has been parked outside her apartment since her disappearance. When she gained access to the vehicle, Coles’ cellphone and purse were inside.

A family friend, Regina Kennedy, said Coles had a lunch bag in the car as though she planned to go to work the day she vanished, the Tribune said. People magazine reported that Coles was seen on a neighbor's security video Oct. 2, dressed for work as she walked near her home.

See the neighbor’s surveillance video, obtained by Fox 32 in Chicago, below.

Dan Perkins, Phillips' boyfriend, told WGN-TV in Chicago that Coles passed up her car instead of getting in.

"She seen something that made her turn around that fast and cross the street, and her car was on the other side of the street," Perkins told the news station

Despite being dressed for work, Coles never made it to start her shift.

Post office officials told her family she called in sick, People reported. Officers conducting a welfare check at Phillips' request found Coles' keys and wallet inside her apartment, the magazine said.

Everything else was in its place -- except her daughter, Phillips told NBC Chicago.

"I'm too scared to feel anything," Phillips said. "I don't want to fear the worst."

Postal Inspection Service spokeswoman Julie Kenney said Monday, when the reward was announced, that her office -- which serves as the investigative arm of the U.S. Postal Service -- is investigating Coles’ disappearance in conjunction with the Chicago Police Department. Coles was not on duty when she vanished, but the agency has the ability to investigate crimes against its employees.

"At this point, anything is possible," Kenney told the Tribune. "We're just looking for information."

Chicago's branch of the National Association of Letter Carriers has also offered a $2,500 reward and a Chicago-area activist added another $1,000 to the pot, the newspaper said.

According to fliers seeking to find Coles, she is a black woman with a medium brown complexion, brown eyes and black hair. She is 5 feet, 4 inches tall and weighs about 125 pounds.

Coles has two tattoos: a heart on her right hand and the words “Lucky Libra” on her back.

Anyone with information on Coles’ whereabouts is asked to call the Chicago Police Department at 312-747-8274 or the U.S. Postal Inspection Service at 877-876-2455.