FARMINGTON — A Franklin County grand jury indicted a Massachusetts man Thursday on a charge of murder in the fatal stabbing of Grace Burton, 81, of Farmington on June 21, 2011.

Juan Contreras, 27, of Waltham, has been held without bail since his arrest in Massachusetts on Nov. 17, 2011.

According to a police affidavit, Burton was stabbed 35 times and died as a result of the wounds.

At the time of the murder, Contreras was living on Pillsbury Lane, off Fairbanks Road, less than a quarter-mile from the Margaret Chase Smith Apartments on Fairbanks Road where Burton lived, according to police.

He is accused of cutting a screen and entering a window to Burton’s residence.

Police were able to match Contreras’ DNA in blood found at the scene after five months of investigation. He voluntarily gave a DNA sample to Maine State Police on Nov. 16 in Massachusetts.

If Contreras is convicted of the charge, he faces a minimum of 25 years and a maximum of life in prison.

According to Trooper Abbe Chabot’s affidavit, police discovered an open window at the back of Burton’s home and the cut screen.

The affidavit states that a witness reported seeing a man of medium stature walking behind an adjacent facility shortly after the stabbing. The tracking dog of Franklin County Sheriff’s Cpl. Nate Bean followed the scent from Burton’s apartment to Sunny Hill Apartment Complex within minutes of Burton’s 911 call.

At a Nov. 3 meeting with State Police Detective Randall Keaten, Farmington police Sgt. Michael Adcock presented Keaten with an incident report dated July 23. In this report, a person by the name of Juan Contreras had crashed his bicycle near the intersection of Oakes Street and the Wilton Road in Farmington.

At the time, Contreras reported an address of 114 Pillsbury Lane in Farmington. In speaking with Contreras, Adcock learned that Contreras was staying at the Pillsbury address but was moving back to Massachusetts in a couple of days. No DNA sample was requested from Contreras at that time and his profile wasn’t in the system.

After more investigation Keaten found two incident reports where Contreras was a witness to different assaults. In each, Contreras was accompanied by his girlfriend, Amanda Pressey. A detective interviewed Amanda Contreras on June 21 and she told him she was baby-sitting at Sunny Hill Apartment Complex.

Keaten knew that Amanda Contreras was Amanda Pressey, the affidavit states. Keaten visited Pillsbury Lane and was told the couple had been evicted a couple of months earlier.

Keaten interviewed Amanda Contreras on Nov. 9. She told police that when she arrived home from baby-sitting in the early morning hours of June 21, her husband was very intoxicated and had a cut on the heel of his right hand. She confronted him about his injury and was told he injured it while whittling on a tree.

Amanda Contreras also told Keaten she had left Juan Contreras in July because he would spend his time playing video games and drinking heavily. She told police her husband was aware that she was baby-sitting at Sunny Hill Apartments the night Burton was killed.

In another interview with Amanda Contreras on Nov. 10, Keaten learned that when police came asking for DNA samples, Juan Contreras ran to the back bedroom and stayed there. Amanda Contreras also told police that Juan had moved back to Massachusetts about three or four weeks after Burton died.

When police interviewed Juan Contreras on Wednesday, Nov. 16, he denied being in Farmington or at Grace Burton’s apartment. He also denied knowing her but gave police a DNA sample. It matched the DNA sample from the windowsill at Burton’s apartment.

dperry@sunjournal.com