(File photo by JEFFREY HASTINGS) A Merrimack cruiser and at least one police officer guarded the Sunset Drive, Merrimack residence around the clock during last year's investigation into the disappearance of 5-year-old Elijah Lewis, whose body was later found in Massachusetts. His mother and her one-time companion are charged in his death.

NASHUA — Joseph Stapf, the one-time boyfriend of the Merrimack mother whose 5-year-old son Elijah “Eli” Lewis was found dead in woods in Massachusetts several months after he went missing from his Merrimack home, has reached a plea agreement with prosecutors on charges stemming from the boy’s death.

Stapf, 32, filed a notice of intent to plea — known as a “NIP” — in Superior Court, which means he has agreed to enter guilty pleas to the charges against him in exchange for certain sentencing guidelines, which in this case involves a State Prison term of between 22 and 45 years.

Stapf, who was originally charged with one count each of witness tampering and endangering the welfare of a child, But since his arrest last October in the Bronx, New York, prosecutors have filed additional charges that include one count each of manslaughter (extended term penalty), second-degree assault, falsifying physical evidence, and witness tampering, according to his case file.

Staph’s sentencing hearing is currently scheduled for Jan. 4 in Hillsborough County Superior Court South.

Also implicated in Eli’s disappearance and death is his mother, Danielle Dauphinais, whose case remains ongoing in Superior Court South.

(Courtesy photo) A photo of Elijah "Eli" Lewis, the 5-year-old Merrimack boy whose mother, and her companion, are accused of causing his death last year.

Dauphinais, 36, is facing first- and second-degree murder charges, along with three counts of tampering with witnesses. A grand jury for the April 2022 term indicted her on the five charges, which accuse her of purposely causing the death of Elijah Lewis, and with causing his death “recklessly, with extreme indifference to the value of human life,” according to the indictments.

Dauphinais and Stapf were together in the Bronx in mid-October last year when New York City Transit officers took them into custody on warrants issued by state and local investigators. They were returned to New Hampshire, arraigned on the charges and ordered held in jail without bail.

Roughly a week after the two were arrested, investigators received information pointing them to a wooded area bordering the Ames Nowell State Park in the northern Plymouth County town of Abington, Massachusetts.

A widespread search was initiated, and within hours a trained cadaver dog located human remains in the woods. A representative of the Massachusetts chief Medical Examiner’s office, using dental records, confirmed the remains were those of Elijah.

Neither New Hampshire nor Massachusetts authorities disclosed whether the information that led them to Elijah’s remains came from Stapf or Dauphinais, or if not, where it did come from.

Photo by JEFFREY HASTINGS Danielle Dauphinais appears at her arraignment via video from Valley Street jail in October.

As for Dauphinais, her case file, which includes numerous motions to seal particular documents, indicates that her next scheduled court appearance is for a motion hearing on Oct. 26.

Dean Shalhoup may be reached at 594-1256 or dshalhoup@nashuatelegraph.com.

Joseph Stapf, 31, last known address, Merrimack