Tenn. mother of four Karen Swift missing since Sunday

(CBS/WREG) DYERSBURG, Tn. - Memphis police are searching for a mother of four who reportedly was last seen in her home by her husband early Sunday morning.

Investigators in West Tennessee have been searching by foot and helicopter for Karen Johnson Swift, 44, after she was reported missing by her husband.

ABC News reported that her 2004 Nissan Murano was found on a road a little less than a mile away from her home with a flat tire. Her cell phone was not inside.

Dyer County Sheriff Jeff Box said that a Tennessee Highway Patrol helicopter used heat sensing technology in an aerial search on Tuesday. The car is also being sent to a crime lab in Nashville for forensic testing.

Authorities say the last sign from Karen was when she used the internet on her phone around 5 a.m. Sunday. Police are working with the phone company to home in on the exact location.

CBS affiliate WREG reported that Swift recently filed for divorce from her husband on Oct. 11th. He has been interviewed by police and has not been called a suspect.

Box said the investigation is being treated as a missing person case and there have not been any signs of foul play. .

However, ABC News reported authorities are suspecting foul play.

Swift's father Gary Johnson told ABC that the family is "worried to death," and that her four children are devastated.

Johnson said, "she had never missed a day since they can remember that she wasn't there to wake them up at 6 a.m."

He speculates that his daughter got a flat tire, and while walking home, something happened to her.

Karen Swift is 5-feet-5 inches tall, 138 lbs., and has blond hair and green eyes. Police ask anyone who may have information regarding her whereabouts to contact the Dyer County Sheriff's Office at 731-285-2802.