Josh Mankiewicz

Who could have imagined it would end like this? January 23rd, 2017. The Woodland Hills neighborhood of Los Angeles. It was just before 5 p.m. when 16-year-old Isabella Semantilli walked into her backyard and found her father seated on the patio in his favorite chair. Except he was slumped over in a pool of blood and she called 911.

Mitzi Roberts was a veteran detective with the LAPD, 29 years on the job, most of them in the Robbery Homicide Division, the unit that handles the city's biggest and most complicated cases.

Mitzi Roberts was a veteran detective with the LAPD, 29 years on the job, most of them in the Robbery Homicide Division, the unit that handles the city's biggest and most complicated cases.

There's no hope of reviving him.

There's no hope of reviving him.

Just a few minutes later, Fabio's wife, Monica, returned home. Soon, LAPD officers were also in the backyard. The TV was on. The fire pit lit. Blood was everywhere. And it pointed the way for police.

Just a few minutes later, Fabio's wife, Monica, returned home. Soon, LAPD officers were also in the backyard. The TV was on. The fire pit lit. Blood was everywhere. And it pointed the way for police.

It led them from the backyard to the kitchen, down a hallway, and into a bedroom.

It led them from the backyard to the kitchen, down a hallway, and into a bedroom.

Drawers were pulled open, their contents on the floor. Investigators also learned that Sementilli's housekeeper had finished working at the home just a couple of hours earlier.

Drawers were pulled open, their contents on the floor. Investigators also learned that Sementilli's housekeeper had finished working at the home just a couple of hours earlier.

Yeah, any blood in the house. Detectives found more blood in the kitchen, on the floor, on the sink. and an empty bottle of vinegar.

Yeah, any blood in the house. Detectives found more blood in the kitchen, on the floor, on the sink. and an empty bottle of vinegar.

And something big was very clearly missing.

And something big was very clearly missing.

Inside the empty garage, detectives saw the circuit breaker box. Nearly half of the breakers had been switched off and one of the garage doors was left open. That led detectives to believe the killer had cut power to the house, then manually opened the garage and left in Fabio's car. What had happened here? This was not a fight.

Inside the empty garage, detectives saw the circuit breaker box. Nearly half of the breakers had been switched off and one of the garage doors was left open. That led detectives to believe the killer had cut power to the house, then manually opened the garage and left in Fabio's car. What had happened here? This was not a fight.

a murder had robbed Fabio's children of their father and left his wife a widow.

a murder had robbed Fabio's children of their father and left his wife a widow.

The investigation into Fabio's murder would uncover unlikely suspects and secret relationships. Can you guys see what's going on there?