The attorney for a man suspected of fatally stabbing his brother-in-law and injuring his wife and her mother at a Patty Jewett neighborhood home on Halloween night last year had two words for the court on May 26: “Not guilty.”

Bound at his hands and dressed in an El Paso County orange jumpsuit during Tuesday’s arraignment, Matthew Regnier, 34, left it to a jury to decide what happened inside his home before police arrived and found a man and two women barely clinging to life, as well as Regnier naked and covered in blood while holding his 2-year-old son.

Scheduled to last three weeks, the trial for the former Monument Academy art teacher is on the books for Oct. 20.

He is staring down the possibility of life behind bars if found guilty.

At an earlier evidence hearing, both sides in the case appeared to agree about the moments leading up to the stabbing, which transpired inside the bedroom of the home located in the 1400 block of North El Paso Street.

A Colorado Springs police detective formerly testified that the wife, who was headed for a divorce with Regnier, told police that the incident escalated to violence over a dispute with their son after he started to cry.

When the wife came in and asked to comfort the child, Regnier allegedly refused. Things turned for the worse when the woman allegedly put her hands around Regnier’s neck in an attempt to get the child back, according to previous Gazette reporting. The other two victims came into the room to assist, and at this point, Regnier is alleged to have pulled out a knife and stabbed the trio, each several times.

From the beginning, Regnier has maintained he was acting in self-defense. The defendant told detectives he recorded a video of the incident, but one detective testified the video’s angle primarily focused on a bedroom wall that became splattered with blood. A detective also noted in his arrest affidavit that physical evidence obtained at the scene does not support the self-defense claim.

The brother-in-law, later identified as 31-year-old Raymundo Cabrera-Medina, died in the hospital from stab wounds to the face, neck, chest and hands. The mother-in-law and wife also suffered life-threatening injuries, including a cut to the mother-in-law’s wrist that one witness said looked “like an amputation,” The Gazette previously reported.

Regnier sustained a finger injury and documented injuries to his groin area. Notably, no neck marks have been mentioned in his court hearings.

Neighbors who knew the family described the stabbing as something that was “out of the blue” for their “neighborly neighborhood.”

Regnier is scheduled for several hearings ahead of his trial date, including a motions hearing on Sept. 3.

He is being held inside the El Paso County jail on a $1 million bond as he awaits trial.