Father's tragic final act as he was stabbed to death on his 51st birthday by his son, 17, who also killed his mother and 12-year-old brother in senseless rampage is revealed

The tragic final act of a father who was stabbed to death by his own son just hours after celebrating his 51st birthday has been revealed. 

Fabio Chiarioni, from Paderno Dugnano, near Milan, Italy, died alongside his wife and 12-year-old son on Sunday after his 17-year-old son brutally slaughtered his family in a horrifying attack in their home. 

It has now emerged that the teen first struck his 12-year-old brother while he slept. His parents were woken up by the young boy's screams and rushed into his bedroom.

The worried father, who did not know his eldest was the attacker, screamed at him for help, only to then slain by his own flesh and blood.  

'I stabbed dad while he was yelling at me to call for help', the teen confessed, as reported by Italian outlet Il Difforme. 

The boy also chillingly told investigators: 'There is no real reason why I killed them. I felt like a foreign body in my family. Oppressed. I thought that by killing them all I would free myself from this discomfort'.

Father Fabio Chiarioni, 51, was killed by his son just hours after celebrating his 51st birthday

Officers dashed to the family home after the teen called authorities and informed them he had killed his father

According to local reports, the young boy had initially told authorities the fabricated story that he had witnessed his father, killing his mother, Daniela Albano, 49, and brother - before taking a knife and stabbing his father.

The 17-year-old explained to investigators that he entered his brother's room on the second floor of the family home to find Chiarioni sitting on a chair with the knife next to him.

He told officers the body of his mother was on the ground by his father's feet, and his brother was laying dead in his bed before he launched his attack on his father. 

But the police were left unconvinced at the story as the boy had no signs of struggle on his body and the truth emerged during a second interrogation.

The teen revealed to investigators that he had felt 'discomfort' within his family, and that these emotions had erupted just a few hours after the family celebrated Chiarioni's 51st birthday.

He also said he had been thinking about carrying out the killings 'for a while,' reports Il Messaggero. 

The boy explained how at around 2am on Sunday morning, he grabbed a large kitchen knife and lunged first at his little brother, plunging the weapon into him at least ten times.

He then made his brutal attack on his parents who were also in his brother's room, but the young brother was found to have the most stab wounds.

A boy, 17, (pictured bottom left) slaughtered his entire family early on Sunday morning, just hours after they celebrated his father's (pictured top left) birthday

The teen's mother, Daniela Albano, 49, was found dead in her nightwear in the room of her youngest son, who had also been killed

Family friends and the mayor of Paderno Dugnano, Anna Varisco, expressed shock at the news of the devastating killings

The teen called authorities immediately after the savage killings, telling Italian emergency services that he had knifed his father to death. 

L'unione Sarda reported the boy had told authorities: 'I killed my dad, come,' following the attack. 

When officers arrived outside the family home, they found the 17-year-old on the pavement in his underwear and with his bare back covered in blood.

He was reportedly still holding the blood-soaked knife in his hand until the authorities arrived, where he then dropped it to the ground.

Officers then found the parents and brother dead in their nightwear in the brother's room. 

Speaking to investigators during his confession, he said: 'I realized it a minute later. I understood that it was not by killing them that I would be freed.'

According to a report by Ansa, the boy has now been arrested for his killing spree after being questioned all of Sunday by investigators headed by Milan juvenile prosecutor Sabrina Ditaranto.

Judicial sources said they yet to understand the motive behind the triple homicide.

'It will be necessary to wait for a long time before explaining such an atrocious gesture', they said.

Ditaranto said during a press conference Sunday: 'The boy understood that he had done something irreversible, he expressed his own discomfort, not related to the family. 

'From a judicial point of view we do not have a technically valid motive. From a sociological and psychological point of view obviously the investigations are open'.

Family friends and the mayor of Paderno Dugnano, Anna Varisco, expressed shock at the news of the devastating killings.

'They were a normal, serene family, not followed by social services and described by everyone as not having problems', Varisco told the outlet.

Neighbors described the family as quiet, well-off , hardworking people, reports Il Messaggero. 

'They were a fantastic, happy family. It's impossible, I don't know what could have happened,' said the father of a classmate of the 17-year-old. 

'He went to school with my daughter, elementary and middle school, we vacationed together, I saw the father a month ago for the last time. 

'We spent good days together in the past.'