D.C. police are seeking information about a 15-year-old girl who has been missing since last summer.

Joanna Delvalle left her mother's District home near Takoma Park on July 21, 2012, when she was 14 years old. She has not returned to her family.

Shortly before Joanna went missing, the teen's family had moved to the D.C. area from New York City. Joanna was upset about relocating and may have returned to the Big Apple. She could be in the Bronx or Queens, but it is also possible that she is still in the District, said Maureen Heads, of the National Center for Missing and Exploited Children, or NCMEC.

Although Joanna voluntarily left home, authorities are still concerned about her well-being.

"There is no indication of foul play. However, she is away from her family, and she has not been in school," said D.C. police spokeswoman Gwendolyn Crump.

Heads said that Joanna's age and length of disappearance are particularly troubling, as is the fact that the teen could have traveled to New York.

"It's always a challenge to find someone in large metropolitans," Heads said.

Joanna is described as a Hispanic female, about 4 feet 9 inches tall and about 130 pounds. She has brown eyes and a pierced nose. The teen has black, curly hair that was dyed brown at the time that she went missing. She usually wore her hair in a bun.

Anyone with information on Joanna can call NCMEC at 800-THE-LOST (843-5678) or D.C. police at 202-727-9099.