The Florida school shooter Nikolas Cruz watched his adoptive father die when he was just five years old and was bullied relentlessly by his younger brother through his teens, new reports have revealed.

New details that have emerged paint a disturbing photo about the home life of the 19-year-old who opened fire on his former classmates and teachers at Marjory Stoneman Douglas High School on February 14.

When he was just five, in 2004, Cruz watched his adoptive father Roger Cruz die of a heart attack, reported the Sun Sentinel.

And years later, the disturbed teen reportedly tried to kill himself by guzzling gasoline just days before he would turn 18.

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New details that have emerged paint a disturbing photo about the home life of the 19-year-old who opened fire on his former classmates and teachers at Marjory Stoneman Douglas High School on February 14

When he was just five, in 2004, Cruz watched his adoptive father Roger Cruz die of a heart attack, reported the Sun Sentinel. Cruz is pictured as an infant with his adoptive mother, Lydia

And later in life he was bullied by his younger brother Zachary, with whom he had a tumultuous relationship. Because he was socially awkward and had a hard time making friends, their mother forced Zachary to bring Nikolas along when he was going out. The brothers are pictured left in a childhood photo and right at their adoptive mother's funeral

When Nikolas Cruz was five he was sitting in the den with his adoptive father, Roger, who he reportedly had a very close relationship with.

But suddenly the youngster ran into the kitchen crying, and his mother Lynda asked if Roger had punished him.

'Nope,' he answered. 'Daddy's dead.'

His home life worsened as he got older and later in life he was bullied by his younger brother Zachary, with whom he had a tumultuous relationship. Because he was socially awkward and had a hard time making friends, their mother forced Zachary to bring Nikolas along when he was going out.

The 18-year-old distraught brother admitted to the Palm Beach sheriff's deputies that he and his friends often picked on Nikolas, saying he deeply regretted it.

'Zachary wishes that he had been "nicer" to his brother,' the report said.

As young as three years old Cruz was diagnosed with developmental disorders, and was described as 'lost,' 'lonely' and violent' by people who knew him.

And just days before his 18th birthday in September, 2016, Cruz may have attempted to kill himself by ingesting gasoline.

A peer counselor told the public safety officer assigned to the school, Scot Peterson, that Cruz either had already tried or was thinking about trying to kill himself by drinking gasoline, and that he'd expressed interest in buying a gun.

Five days later he was reported to the state for posting a video of himself cutting his arms on the mobile app Snapchat.

While he was a student at Stoneman Douglas he was once seen in 2017 clutching a dead bird to his crotch during reading class, a former classmate told the Sun Sentinel. Cruz is pictured holding a gun in a social media photo. He was reportedly fascinated by weapons

'He always stared at everyone. He would stare into your soul,' Tyra Hemans, a senior at the high school and survivor of the massacre told the paper. She said she sat across from him during her first period reading class during their junior year

Hemans also said she and her best friend, Meadow Pollack (pictured, one of the 17 victims), recognized that Cruz seemed lonely and attempted to befriend him

While he was a student at Stoneman Douglas he was once seen in 2017 clutching a dead bird to his crotch during reading class, a former classmate told the Sun Sentinel.

'He always stared at everyone. He would stare into your soul,' Tyra Hemans, a senior at the high school and survivor of the massacre told the paper. She said she sat across from him during her first period reading class during their junior year.

One day, she noticed he was holding his hand to his crotch, and quickly realized he was clutching a dead bird.

'I looked close and I saw he was holding a dead bird near his genitalia,' Hemans said.

'I saw some feathers and I knew it was a bird. That was disturbing. But I just looked away because it wasn't by business.'

She said she wondered if Cruz had been carrying the bird around with him all day in his lunch box.

Hemans said she didn't tell a teacher about the dead bird incident, but did tell her best friend, Meadow Pollack.

Pollack was one of the 17 people mowed down by Cruz during his Valentines Day rampage with an AR-15 assault weapons.

And though she and Pollack were disturbed, Hemans said they kept it to themselves, instead trying to befriend him.

She said he seemed lonely, and they would lend him their cell phones during class so he could use it for assignments.

These new details come as it has been revealed that on that Wednesday afternoon Cruz attempted to murder many more people, taking position at a third floor window that overlooked a courtyard where dozens of people ran from the school for their lives

Cruz is currently booked into Broward County jail after confessing to shooting 33 former classmates, coaches and teachers. He is pictured with his public defenders on February 19

Other details that have emerged about the shooter paint the picture of a teen who was obsessed with guns and war - and someone who was widely known to be a potential threat to his community

On one occasion the FBI received an anonymous tip that Cruz had taken the bird home and cut it open in his kitchen, so he could see what was inside. It's not clear if this is the same bird Hemans had seen Cruz carrying around with him.

These new details come as it has been revealed that on that Wednesday afternoon Cruz attempted to murder many more people, taking position at a third floor window that overlooked a courtyard where dozens of people ran from the school for their lives.

He was reportedly trying to shoot through the window of the third floor teachers lounge into the courtyard below him, but was thwarted by hurricane-resistant glass windows. The windows only so much as cracked as he repeatedly shot at them.

Cruz is currently booked into Broward County jail after confessing to shooting 33 former classmates, coaches and teachers.

Other details that have emerged about the shooter paint the picture of a teen who was obsessed with guns and war - and someone who was widely known to be a potential threat to his community.

Over 10 years his adoptive mother, Lynda, had to call the police 23 times to report that he'd been physical with his brother and with her.

He was expelled from Stoneman Douglas while he was a junior after being suspended multiple times for fighting and for other disturbing behavior. He was finally ejected after he assaulted a teacher in February 2017.

Just three days later he would buy the assault rifle he used in the massacre.