CASTRO VALLEY, Calif. -- The Alameda County sheriff's department held a press conference Wednesday to announce a break in a 3-year-old case of an unidentified body found behind a Castro Valley restaurant. They said the woman known as Jane Doe had a first name of Adrianna.

Investigators Wednesday identified Miguel Angel Nunez Castenada, 27, who apparently lived in Hayward with Adrianna before she was killed as a "person of interest" in the case.

Detectives said they spoke to Castenada briefly last week, but can no longer locate him.

On May 1, 2003, workers at Carrow's restaurant at 2723 Castro Valley Blvd. in Castro Valley found the body of a girl of mixed race believed to be between 12 and 17 years old, strangled to death, stuffed into a large green canvas bag and dumped behind the eatery.

SLIDESHOW: View Images From Case

The sheriff's department said it believes Castenada could be in Southern California and could be on his way back to his native Mexico.

Castenada would be in the country illegally if located and has been deported in the past, according to the sheriff's department.

Alameda County Sheriff's Sgt. Scott Dudek said if authorities find Castenada, they will arrest him only on illegal immigration charges at this time, as they don't yet have enough information to arrest him on homicide charges.

Castenada's former roommate Jose Reyes spoke to NBC11 Wednesday.

"I don't know what to say what to think ... I still can't believe it," Reyes said.

Police said the relationship between Castenada and Adrianna was either husband/wife or boyfriend/girlfriend.

On Tuesday, the Alameda County Coroner's Office issued a press release saying it had determined the victim's death to be a homicide.

Investigators have spent the past three years keeping the case in the public's attention.

The released pictures of the clothing the woman was wearing when she was discovered.

They also made a 3-D model of the woman.

She was about 5-foot-1, approximately 110 pounds, had long, dark-brown wavy hair, and a light-medium complexion. She was wearing a red, white and blue "Tommy Sports" shirt, blue plaid pajama pants and ankle socks with a snowflake pattern.