The Amber Alert for a missing Fort Worth girl was reissued Wednesday and extended to New Mexico.
The FBI is assisting Fort Worth police in the search for 11-year-old Jessica Smith, who disappeared late Monday night or Tuesday morning.
Police said they believe 42-year-old Kimberly Smith took her daughter Jessica, who is 5 feet 1 inches tall and weighs approximately 120 pounds. Jessica has brown eyes and straight, brown hair just past her shoulders in length.
Smith's mother has a cross tattoo on her neck and a decorative tattoo on her back. She is 42 years old and stands 5 feet 2 inches tall. She weighs approximately 150 pounds and has brown hair and brown eyes.
Officers are searching for a 2007 silver Mazda CX-9 sedan with Texas license plate BMZ-390. The car has tinted windows and a pink and green Harley-Davidson sticker on the rear window.
While Amber Alerts for children who are with a parent with legal custody are unusual, police said they issued the alert because Jessica's life could be in grave danger.
On Tuesday, Fort Worth police said Smith assaulted Jessica in a domestic violence dispute at their home Monday evening. Family members said the girl was not seriously injured.
Police said Smith apparently has a deteriorating mental illness and has threatened to commit suicide and injure her children. Police also said Smith has exhibited a pattern of irrational behavior.
Family members said Tuesday that they fear Smith may left North Texas and could be in Oklahoma, where her former husband lives, or New Mexico.
KOB-TV in Albuquerque, N.M., said Wednesday there have been no reported sightings of Jessica there.
Amber Alerts expire every 24 hours. Fort Worth police reissued the alert for Jessica on Wednesday.
Tammy Vu, a seventh-grader, said she is worried about her friend Jessica.
"I tried calling her yesterday, and it started ringing, but she didn't pick up," she said. "But today it didn't ring at all."
Vu said her call went straight to Jessica's voicemail.
Investigators said they believe Smith took Jessica from her home in the 7300 block of Indiana Avenue in far North Fort Worth between 10 p.m. Monday and 6 a.m. Tuesday.
Fort Worth investigators have received no tips in the case.
Sixteen-year-old Caitlin Fields, one of Jessica's two older sisters, told NBC 5 on Tuesday that the family was concerned.
"Last night ... there was a lot going on, and they were arguing, and she wouldn't let Jessica go, so me and my sister had to get her away from there," she said. "And then, I guess, this morning she was just like, 'Oh, know what? We're leaving.'"
Fields said their mother is going through a divorce, has been under a lot of pressure and recently made some threats.
"She's been going through a lot right now, with the divorce and stuff," she said. "And my little brother, actually, just recently left [and] moved up with my dad, so she's been having a lot to deal with. ... I guess she just, finally, cracked."
Administrators at Parkwood Hill Intermediate School called police before 10 a.m. when the fifth-grader did not show up to school. Officers performed a welfare check at her home at about 10:30 a.m.
Anyone with information is asked to call 911 or the Fort Worth Police Department at 817-335-4222.
NBC 5's Scott Gordon, Amanda Guerra and Randy McIlwain contributed to this report.