The gates to the Athol Wastewater Treatment Plant were locked and no activity was observed Monday afternoon on Jones Street in Athol. The body of a female was discovered near the entrance early Monday morning and authorities have launched a homicide investigation into her death.

ATHOL — Authorities are treating the death of Kelsey Clifford, 26, as a homicide, a Northwestern District Attorney spokeswoman specified Thursday.

Officials previously only stated the incident was “criminal” in nature. Clifford’s body was found in the early morning of Monday, Nov. 11, near the entrance to a wastewater treatment plant in Athol. Pending an autopsy, the official cause of death will be determined by the Office of the Chief Medical Examiner.

“It is being investigated as a homicide. No arrests have been made, the investigation remains active and ongoing, and we have no reason to believe the public is in harm’s way,” said Northwestern District Attorney spokeswoman Mary Carey, adding no further information is available at this time.

Clifford’s death is under investigation by the Massachusetts State Police assigned to the Northwestern District Attorney’s office and the Athol Police Department.

The 26-year-old from Leominster was found by the wastewater treatment plant on Jones Street, which is surrounded by woods, but close to a densely populated area. The plant was closed on Monday for Veterans Day, with access to the plant blocked off by a chain-link fence and padlock.

At 4:58 a.m. Monday, Athol Police responded to Jones Street after reports that multiple people were sleeping in tall grass with a vehicle parked nearby. Authorities have not stated whether this tip led to the discovery of Clifford’s body.

Around 7 a.m. that morning, the Fire Department responded to Jones Street with the Engine no. 4 pumper to assist police, and returned again at 1:49 p.m. with their Special Ops SPS pumper (Engine no. 2), which is used for incidents involving a high possibility of hazard, including car accidents, rescues and extractions.

Also, at 1:15 p.m. that day, police received a call from a party reporting a person “saying suspicious things on his cell phone,” and seen wearing a red Patriots jacket and hat walking on Harrison Street, which connects with Jones Street. Again, authorities have not stated whether these incidents are connected in any way to the discovery of Clifford’s body.

Candlelight vigil

Family and friends mourning Clifford’s tragic death will gather for a candlelight vigil this Sunday, Nov. 17. Open to all who knew her, the vigil will begin at 6 p.m. on Sargent Street (at the end of the cul de sac) in Leominster.