When Joe Gonzales left for his son's Boy Scouts meeting the night of April 6, 2011, his wife and stepson were snuggled on couches, watching a movie before what was to be a late family dinner.

An hour later, firefighters emerged from the North Highlands home with the bodies of 8-year-old Wilfred Villarruel and his mother, Laura Fernandez, as flames leapt to the sky.

The midevening fire seemed suspicious from the start, and it wasn't long before investigators ruled it an arson. But within days, arson and homicide detectives were asking a terrifying question: Was this a double homicide – or a murder-suicide?

That question haunts Sacramento County Sheriff's Detective Tom McCue to this day. The evidence in the case is maddening, the scenarios it points to mind-boggling. And while both explanations – that a mother killed her son, or that a stranger killed both – are stomach-churning, McCue said having no resolution at all is what troubles him.

"I think I could swallow this case one way or the other … but I don't have those answers for anyone," said McCue, a six-year homicide veteran. "This has never settled with me."

As with many death investigations, detectives turned their attention first to those closest to the victims.

Gonzales had a steadfast alibi at the Scouts meeting, McCue said. Detectives couldn't nail a motive anyway: There was peace in the home, according to family, and Gonzales reaped no financial benefit from the deaths, McCue said.

The boy's father, Pablo Villarruel, also quickly passed scrutiny. McCue said Villarruel seemed genuinely devastated by Wilfred's death, and cellphone data didn't put him anywhere near the scene.

There were no estranged boyfriends or other usual suspects, McCue said, and detectives were not able to link the crime to any others, deflating any notion that it was the work of a serial arsonist.

So, as more than a dozen detectives gathered in a conference room at the sheriff's Centralized Investigations Division days after the fire, someone offered up the murder-suicide theory.

"We all looked at each other," McCue recalled of the meeting. "Nobody had voiced it (before that point), but we were thinking about it."

McCue acknowledges he has no concrete evidence to support that thesis – but is quick to add there is no solid evidence otherwise. So both scenarios remain on the table.

In talks with relatives, McCue said detectives learned money had been a stressor for Fernandez and Gonzales. They had occasionally taken handouts from friends, but they hated taking charity.

Additionally, Fernandez, 37, felt "isolated and really bothered by her past," relatives told McCue. Much of that involved her struggle years earlier with the loss of Wilfred's brother, who died of a brain tumor.

Could that have been enough for Fernandez to snap? Was it that she wanted to reunite with her dead son, and bring Wilfred with her?

Perhaps the biggest hole in that theory is the lack of any gas container that had to have been used to set up the fire.

Arson investigators detected large amounts of accelerant – in this case, gasoline – in several areas of the home, McCue said. So much was used that some sort of container had to have been used – and detectives found none.

It is possible Fernandez used a cooking pot or some other household object, and then cleaned it thoroughly to eliminate residue before setting the fire, McCue said. But rarely do suicidal people take such care to eliminate evidence unless they want to make it look like an accident, the detective noted.

The scene itself offered detectives little help.

Investigators found three ignition points for the fire – the garage, where the fire was the most intense, the master bedroom and the bedroom where the bodies were found.

Had somebody else set the fire as Fernandez and her son watched a movie, they would have had easy escape routes out the front or back door. So why were they in a back bedroom?

It was too early for bed, especially because the family always ate late on Scouts night, McCue said. He wonders whether an intruder forced them into the back bedroom before setting the fire there, and, on his way out, igniting the garage fire.

From that bedroom, Wilfred and his mother would have had trouble reaching the front or back doors because the fire from the garage and master bedroom likely would have been too intense, McCue said.

The room did have an escape route – a window, which the victims could have reached by climbing a dresser. But if that fire already was burning, McCue said, the heat alone would have blocked them.

Pathologists found injuries to Wilfred's face, raising the possibility he was hurt or even knocked out before the fire, McCue said. But firefighters said they could have caused the injuries trying to save him – or they could be from a ceiling fan that melted and fell to the ground, the detective said.

The home's back door was unlocked, which could have given an intruder access. Detectives don't know whether the front door was locked because firefighters kicked it in.

No matter who set the fire, McCue said Fernandez and her son likely were dead in minutes. The fire was so explosive that it fractured window glass, blew one door off the hinges and a 2-foot-wide hole in another.

Efforts by The Bee to reach Gonzales, who has since lost touch with detectives, were not successful. Pablo Villarruel did not return a phone call, though he told The Bee after the fire that he was deeply troubled by the strange circumstances surrounding the fire.

Blanca Velazquez, Fernandez's sister, said Fernandez was a "whole different person" the year leading up to the fire. She was distant, Velazquez said, and had distanced herself from her family, possibly because of a disagreement over Gonzales.

Still, Velazquez said she could never imagine her sister doing something so awful. She said Fernandez showed great compassion for her young son, Alex, when he died in 2007 – how could she hurt her only son?

"That's not my sister. I'm pretty sure she didn't do this," said Velazquez, 42. "I know she loved him so much and I know the sacrifice she (made) with Alex."

McCue has run the case by arson investigators and even an FBI profiler. Fierce debates among his own squad have detectives convinced one way or the other – only to flip-flop after further thought.

The case file lingers on McCue's desk. On the cover is a grainy photo of firefighters kneeling on a lawn. You can't see Wilfred's lifeless body, but McCue knows it's there.

It is one of three cases of his homicide career that will never fade from his mind, he said. If nobody comes forward with information that confirms either theory, he said, the case will languish, unsolved, and "it'll stay with me forever."

Anyone with information about this case is asked to call the sheriff's homicide bureau at (916) 874-5057.

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Call The Bee's Kim Minugh, (916) 321-1038. Follow her on Twitter @Kim_Minugh. Bee researcher Pete Basofin contributed to this report.

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