WASHINGTON (WASHINGTON POST) - Grant Amato had a problem and it was ripping his family apart.

Outside the walls of his family's well-manicured home in a rural area north-east of Orlando, Florida, the 29-year-old could have been mistaken for another luckless young man surfing through a bad patch - lost his job, kicked out of school, living at home.

But inside the house, Amato was allegedly gobbling up whatever money he could steal. He lifted US$150,000 (S$202,800) from his parents, Chad and Margaret. His brother Cody lost US$60,000; when that was gone, Amato allegedly stole his brother's guns and sold them. Amato even allegedly took out a US$65,000 loan on the house.

Amato flung all that money through his Internet connection, police say, where it landed more than 9,000km away in the Balkans. Since last June, he had been communicating with a Bulgarian woman - who has not been publicly identified.

They met on Cam Girls, a live-streaming pornographic website. In three months, he had paid out more than US$200,000 to interact with the woman.

His family knew he had stolen the money, and they knew where it was going. His mum and dad demanded Amato enter rehab for a pornography addiction last December. Promises were made, a contract signed between parents and son.

The family drama hit such an intense pitch that Cody confided to his girlfriend he was worried his brother "would kill everybody", according to an arrest affidavit filed recently by the Seminole County Sheriff's Office.

The authorities now believe he did.

Last Friday morning (Jan 25), police discovered inside the family home the bodies of Chad, 59, Margaret, 61, and Cody, 31.

All had been gunned down in what a police affidavit described as an "execution-style" shooting.

Amato is now in police custody facing three first-degree murder charges. Police alleged his obsession with the girl across the Atlantic propelled Amato to violence.

"I think we have some mental health issues," Mr Jeffery Dowdy, the defendant's attorney, told reporters this week, according to Orlando's Fox 5.

"A few months ago... he had checked himself into an Internet sex addiction facility in Fort Lauderdale. He had walked off there."

As Amato's hours and money were beginning to be consumed with his overseas obsession last year, his life beyond the computer screen was also coming undone.

On June 21, 2018, Amato was working as a registered nurse at AdventHealth Orlando. According to a police report, hospital staff discovered eight empty vials of propofol, a medication used as a sedative before surgery, in two rooms Amato was overseeing.

No doctors had ordered the drugs, and records indicated Amato had taken them from a storage machine.

When confronted about the unauthorised drugs, Amato told hospital authorities "he administered the drug to patients who were not being adequately relaxed", the police report stated.

The hospital believed he had previously improperly administered propofol as well.

During the confrontation, Amato expressed suicidal thoughts, and the police were called.

Officers arrested Amato and the hospital said it planned to prosecute, according to the police report, though public records do not indicate that charges were ever filed.

Amato's brother's girlfriend later told police he was then kicked out of anesthesiology school.

Amato's online relationship intensified, meanwhile, and he continued sending large sums of money overseas.

The family, watching Amato's online infatuation drain their bank accounts, reached a tipping point.

According to the arrest affidavit, on Dec 22, his father Chad called a family meeting, along with Margaret, Cody, and eldest son Jason.

Chad told Amato that if he wished to stay at their house, he needed to enter a 60-day sex and pornography rehabilitation centre in Fort Lauderdale.

He agreed to go, but walked away from the centre before his treatment was complete on Jan 4.

After returning home, his father presented Amato with a two-page list of rules he was required to follow if he wanted to live at home.

One of the conditions was that he cease all communication with the Bulgarian woman.

According to the arrest affidavit, Amato would later explain to police that he agreed, "but he didn't think they were fair because he felt that the Bulgarian female was his girlfriend and they had a relationship".

He continued, however, to communicate with the woman over Twitter, according to the arrest affidavit.

Not much later, his father discovered the messaging was still going on. Last Thursday, the family again confronted Amato, telling him he had to get out of the house.

That night, Amato's brother Cody was with his girlfriend when he received a call from his father asking Cody to come home.

When the girlfriend asked what was wrong, he replied that it was "stupid" family nonsense, the arrest affidavit said.

Later, she texted her boyfriend for a status update. "(A)ll ok," he wrote back.

But when Cody did not show up for work the next morning, the girlfriend called the police to check on the family.

Sheriff deputies arrived to the house at 9.17am last Friday. No one answered the knocks.

The windows and doors were all locked. Calls to the family members went unanswered. The deputies even blasted the cruiser's air horn, but no one stirred inside.

A deputy eventually slipped the deadbolt on the back door using a knife.

Chad was lying on his back on the kitchen floor, blood pooling across the ground. Cody was curled into the fetal position on the floor of a storage room. Margaret was sprawled over the desk in her home office. All had been shot and a 9mm handgun was recovered at the scene.

Amato's 1996 Honda Accord was missing from the house. Law enforcement put out a bulletin for the car, and the next day police tracked the Honda down to a DoubleTree Hilton Hotel in Orlando.

Approached by investigators, he agreed to sit for an interview. Amato described the family drama stemming from his relationship with the Bulgarian woman.

But he denied killing his family, instead claiming he left the house after his father confronted him about the Twitter messages.

Later, Amato said he returned to the house and saw police and news vehicles outside the house. He claims he fled again.

After showing Amato ghastly pictures of the crime scene - his father face up on the kitchen floor, his brother curled up in the storage, his mother spilled over her desk - investigators asked Amato is if he "had any remorse".

According to the arrest affidavit, his "response was his family had been blaming him for months for ruining their lives, stealing and not following the rules of the home, so he might as well be blamed for this too".

Court records indicate Amato will be formally arraigned on the charges on March 26. The authorities have not signalled whether the unnamed cam model is facing any charges related to the deaths.