The search for evidence in the Melanie Melanson case appeared to ratchet up yesterday.

In what the district attorney's office would only confirm to Patch was "an evidentiary search," a Patch reporter yesterday saw at least three helicopters flying above the area near the Kraft Foods plant.

And MyFoxBoston reports that a Melanson family member was present at yesterday's search.

At least some of the copters are reported to be from the Massachusetts State Police Air Wing, said to be taking photographs of sites where excavation for Melanson's body had taken place.

Melanson went missing in 1989 after attending a party in the woods with a group of friends. The Woburn High School freshman was last seen with two boys, who have maintained for 23 years that they have no knowledge of what happened to the teenager.

This past summer, a private investigator and some volunteers renewed the search for the missing Melanson, hoping to find new evidence.

Authorities are still searching for Melanie or any information related to the case. Members of the public with information that they believe would be helpful to the investigation can contact the Woburn Police Department at 781-933-1212 x853 or State Police assigned to the Middlesex District Attorney’s Office at 781-897-6650.