Authorities combed an area near a Kraft Foods plant in Massachusetts Wednesday for clues in the case of a 14-year-old girl who disappeared 23 years ago. 

Three helicopters with the Massachusetts State Police Air Wing flew over the area and took photos of an excavation in the renewed search for Melanie Melanson, the Woburn Patch reported. 

Melanson was five days shy of her 15th birthday when she vanished in October 1989, after attending a party with friends in a wooded area near the Woburn-Stoneham town line. Authorities believe the girl was killed, but her body has never been found and no suspects have ever been named in the case.

The girl's relatives were reportedly on site Wednesday when investigators searched the area. 

In a July interview with FoxNews.com, Jessica Pastore, a spokeswoman for the Middlesex County district attorney's office, said, "We don't believe she ran away. We believe that she's deceased."

"We're hopeful that we can find Melanie and give her the proper burial that she deserves," said Pastore, adding, "We know who was with Melanie the night she disappeared."

Melanie, then a freshman at Woburn High School, was the youngest attendee at the party on Oct. 27, 1989, in a wooded hangout popular to area teenagers. In the hours immediately following her disappearance, authorities suspected the girl may have run away, but later concluded that she was likely killed.

A $5,000 reward is being offered for any information leading to Melanie Melanson's remains. Anyone with information on her disappearance is urged to contact the Woburn Police Department at 781-933-1212, ext. 853, or State Police assigned to the Middlesex district attorney's office at 781-897-6650.

FoxNews.com's Cristina Corbin contributed to this report.