Neil, the autopsy guru, led the way. “ME confirmed that the mother, Denise Harrington; the older son, Jacob; and the younger son, Oswald, all died of a single knife wound. Of note, there are no hesitation marks on any of the wounds.”

“Christ,” Phil muttered, the lone family man in the room.

“The girl, Molly, suffered a knife wound to the upper left arm. Cause of death, however, was manual asphyxiation. Fractured hyoid bone, which indicates a perpetrator of considerable manual strength.”

“Like a nine-year-old boy?” D.D. spoke up.

Neil gave her a look. “Not likely.” He glanced back down at his notes. “As for the father, Patrick Harrington, ME hasn’t gotten to him yet. According to the doctor’s report, however, he died due to complications from a gunshot wound—swelling of the brain.”

“Okay. So three stabbed, one strangled, one shot. Kind of original right there. Most family annihilators have a singular approach, don’t they?” D.D. looked to Alex for an answer.

He nodded. “Traditional approaches include shooting, drugging, and/or carbon monoxide poisoning. Sometimes, you see a case where the father figure drugs the family first, presumably to limit their suffering, then shoots them. If we look at teenage family annihilators—the abused son seeking retribution—methodology expands to bludgeoning and/or arson. I haven’t heard of a case where a single attacker switches weapons as he/she goes along.”

“Single attacker,” D.D. picked up. “Let’s talk about the number of perpetrators for a second. What about cases where the adolescent child has a partner in crime, like the daughter and her boyfriend who kill her family so they can be together. Or wasn’t there a case where a daughter and her lesbian lover murdered her grandparents so they could be together? Stuff like that.”

“When a teenager is the instigator of family annihilation,” Alex said, “there are instances of partner involvement. In those cases, however, both partners murder the offending family members, then escape together. Not kill the family, plus the adolescent instigator, and then the partner gets away.”

“Coconspirator turned on the instigator?”

“Why?” Alex asked.

“Hell if I know.”

“Not probable,” Alex said. “Furthermore, the Harrington scene is methodical. Two teenagers on a killing spree are never gonna get through a house that clean. We’re looking for a perpetrator of above-average strength and intelligence. Patient, calculating, and skilled. Find me that teenager, and we’ll talk.”

“Fair enough,” D.D. said. “What do we know about the knife?”

“The knife used in the Harrington attack matched a set found in the kitchen.” Phil had finished his donut and was brushing crumbs off his rounded belly. “Handle too smeared to yield prints.”

“And the handgun?”

“Registered to Patrick Harrington. His prints on the handle.”

“So murder weapons came from inside the home?”

Phil nodded.

“All right. The Laraquette-Solis scene?”