Evelyn Mae Boswell was not reported missing until Feb. 18, authorities say.

A desperate search is underway in Tennessee for a 15-month-old girl who authorities say was last seen in December.

Evelyn Mae Boswell, of Sullivan County, was entered as a missing child on Tuesday, but she was reportedly last seen on Dec. 26, according to the Tennessee Bureau of Investigation (TBI). A statewide Amber Alert has been issued.

Those who know about Evelyn’s whereabouts are believed to be driving a gray 2007 BMW with front-end damage, TBI officials said. The car has the Tennessee license plate 3M9-6W9.

“Investigators continue to follow-up on leads as they come in,” the TBI added Friday.

Evelyn’s mother, Megan “Maggie” Boswell, has been involved in the investigation along with the father, Ethan Perry, who is on active duty in the U.S. military, stationed in Louisiana, according to the Sullivan County Sheriff’s Office.

Evelyn, who is white and has blonde hair and blue eyes, was last seen wearing a pink tracksuit with pink shoes and a pink bow in her hair. She is about two feet tall and weighs 28 pounds, according to the Tennessee Bureau of Investigation.

Anyone with information regarding Evelyn’s whereabouts is urged to contact the Sullivan County Sheriff’s Office at 423-279-7330 or the Tennessee Bureau of Investigation at 1-800-TBI- FIND.

ABC News’ Ahmad Hemingway contributed to this report.