Chilling details emerge after teen killed his parents and 12-year-old brother on father's birthday

Warning: This article contains details of violent crime which some readers may find distressing.

Further details have emerged after a teen confessed to stabbing his family to death at their home in Milan.

The 17-year-old boy murdered his father, 51, his mother, 48, and his 12-year-old brother on September 1.

Prosecutors said that he first went into his brother's room, where he stabbed him while he was sleeping.

His mother rushed into the room after hearing the 12-year-old cry out, and the teen turned the 20cm knife on her.

The dad, not knowing his son was the attacker, shouted at him to help.

But he instead responded by stabbing his father before he realized what was happening.

The 17-year-old allegedly told police: "I stabbed dad while he was yelling at me to call for help."

He added: "I thought one stab would be enough to kill, then I realised it wasn't like that."

The teen stabbed his father in the neck multiple times, allegedly saying he didn't want his family 'to suffer'.

The teen confessed to the murders (Getty Stock Image)

It's reported that he then called the police and told them what he had done, saying: "I killed my dad, come."

Police said that when they arrived the teen was sitting on a wall outside covered in his family's blood.

Italian newspaper Corriere Della Sera reported that there were 68 stab wounds in total, most of them around the victims' necks.

Prior to the murders the teen told how he had repeatedly listened to The Beatles' song 'The Long and Winding Road'.

He allegedly told police that he had felt like an outsider in his family, saying: "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."

However, the teen reportedly went on to admit that after committing the horrific act he realized this was not true.

He claimed: "I realized it a minute later. I understood that it was not by killing them that I would be freed."

Police said that when they arrived the teen was sitting on a wall outside covered in his family's blood (Getty Stock Image)

Italy has been left shocked by the murders, with sociologist Massimo Crepet telling Italian paper Il Messaggero that the family unit was 'shattered', adding: “On Saturday night half of Italy doesn’t know where their children are.”

As per The Times, Milan juvenile prosecutor Sabrina Ditaranto said she could see 'no real motive'.

She said in a news conference: "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."

Ditaranto added: “He does not give a logical and coherent explanation for what happened.’’

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

"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."