What we do know is what happened next.
At approximately 3:10 a.m. on Christmas morning, Brad returned home.
Inside, he found Bruce Pardo lying on a couch.
Two handguns were nearby.
Pardo had suffered terrible burns.
The Santa costume had melted against parts of his body.
And he had suffered a self-inflicted gunshot wound.
He was dead.
Brad called 911.
The man police were searching for would never be interrogated.
There would be no trial.
No confession.
No courtroom testimony.
No opportunity for prosecutors to force him to listen as survivors described what he had done.
The investigation would therefore have to reconstruct the massacre entirely from survivors, physical evidence, purchases, travel records, court documents and Pardo's movements before his death.
And investigators quickly discovered that his planning extended well beyond the burned house.
The Rental Car Was Not Safe
Near Pardo's brother's home, investigators located the blue rental vehicle.
Inside were remnants connected to the Santa costume and ammunition.
But police could not simply open the vehicle and begin collecting evidence.
Pardo had prepared another trap.
Authorities said items inside the vehicle were rigged so that disturbing them could trigger an incendiary chain involving a flare or similar ignition source, combustible material and ammunition.
A bomb squad responded.
During attempts to render the device safe, it activated.
No one was hurt.
This changed the way investigators understood Pardo's planning.
The trap had no value in the attack inside the house.
Its purpose existed afterward.
It could destroy evidence.
It could injure investigators.
It could create another fire.
It demonstrated that Pardo had thought about what police might do once they found the rental car.
The massacre was not a chaotic eruption followed by improvised escape.
Important parts had been anticipated.
Police then searched Pardo's Montrose home.
They found more evidence of preparation.
Firearms-related packaging.
Shotguns.
Racing fuel.
Equipment.
The pieces from months of planning were now sitting in one location.
The question became unavoidable.
How long had he been preparing?
The answer appeared to be at least six months.
June to December
Put the timeline together.
June 13.
First handgun purchase.
June 18.
Spousal support order.
July.
Job lost.
August.
Another handgun.
September.
Another handgun.
Santa costume ordered.
October.
Another handgun.
Trip to Iowa.
Additional magazines purchased.
November.
Another handgun.
Santa suit collected.
Fuel equipment prepared.
December.
Divorce finalized.
Travel plans purchased.
Rental vehicles acquired.
Supplies packed.
Attorney's home apparently placed into the plan.
Christmas Eve.
Attack.
This was not five minutes of anger.
It was architecture.
One piece added after another.
Weapon.
Weapon.
Disguise.
Equipment.
Travel.
Vehicle.
Money.
Alternate vehicle.
Potential secondary location.
The final crime lasted only a short time.
The preparation occupied months.
That is important when people describe Pardo as "snapping."
Whatever emotional crisis he experienced, the evidence does not fit a simple picture of a man suddenly losing control on Christmas Eve.
Someone who suddenly loses control does not usually order a custom disguise in September.
He does not spread firearm purchases across months.
He does not prepare a second rental vehicle.
He does not carry thousands of dollars on his body.
He does not arrange transportation outside the state.
He does not prepare an incendiary device disguised as a Christmas present.
The violence was deliberate.
What Was the Motive?
Because Pardo killed himself, motive can never be known with the precision that might come from a confession.
Investigators therefore had to distinguish between what they could prove and what they could infer.
The divorce clearly mattered.
Police repeatedly described the split as contentious.
The marriage had ended badly.
Pardo resented financial obligations.
Sylvia kept the dog.
She kept the engagement ring.
He owed her $10,000.
His relationship with his mother had deteriorated partly because she sided with Sylvia.
Investigators believed Sylvia's attorney may have been another intended target.
But no responsible account should reduce nine murders to a dog or a check.
Those were grievance details.
The real decision was much larger.
Pardo apparently decided that the destruction of his marriage justified the destruction of people he associated with that loss.
This is a recurring feature of some forms of domestic mass violence.
The offender stops viewing separation as another person's right.
Instead, separation becomes humiliation.
Betrayal.
Loss of control.
The grievance expands.
The former partner becomes the enemy.
Then her supporters become enemies.
Then relatives become enemies.
Then people who helped her legally become enemies.
That pattern is consistent with police theories in the Covina case, though Pardo's exact internal reasoning died with him.
What is certain is that Sylvia did not kill nine people.
The divorce attorney did not.
The Ortega family did not.
Bruce Pardo did.
Whatever anger he felt remained his responsibility.
The Mother Who Wasn't There
One of the most unsettling discoveries was that Pardo's mother might also have been targeted.
Police learned that she had been invited to the Ortega family's Christmas party.
Her relationship with Sylvia had continued after the marriage deteriorated.
Pardo reportedly resented that closeness.
Investigators believed he expected his mother to be at the Christmas Eve gathering.
She did not attend because she was sick.
That simple change of plan may have saved her life.
She stayed home because she felt unwell.
Everyone at the Ortega house had no idea that attendance could become a life-or-death decision.
This is one of the most haunting elements of mass violence.
Tiny choices take on enormous meaning only afterward.
Leave five minutes earlier.
Sit in the back of the house.
Go upstairs.
Stay home sick.
Answer the door.
Do not answer the door.
None of those decisions feel historic while they are happening.
Afterward, they define who survives.
The Attorney
Investigators found another rental vehicle near the Glendale home of Sylvia's divorce attorney.
Inside were supplies consistent with travel.
Maps.
Food.
Water.
Clothing.
Computers.
Police theorized that Pardo intended to travel from Covina to the attorney's home, attack him and possibly his family, and then switch vehicles before leaving the area.
That plan never happened.
The explosion inside the Ortega home burned Pardo severely.