Teenager, 19, is arrested over triple-murder after stabbing five-year-old half-brother he was babysitting and father and his girlfriend when they returned to their Bronx home following a night out

A New York City 19-year-old has been arrested and checked into a psych ward in connection with the murder of his five-year-old half brother, their father and the child's mother in their apartment building. 

Jayden Rivera was arrested and charged in the grisly-triple murder and also faces manslaughter and criminal possession of a weapon charges, an NYPD spokesperson told DailyMail.com.

The bodies of Jonathan Rivera, 38, Hanoi Peralta, 33, and Kayden Rivera, 5, were found inside an apartment building on 674 East 136th Street in Mott Haven.

Jonathan Rivera is Jayden's father and Peralta is Jonathan's girlfriend and mother of their son, Kayden. 

Police responded to a 911 call at 6:40am on Sunday to discover Jonathan Rivera in the hallway covered in blood with several stab wounds. 

Peralta and Kayden were found shortly after also with multiple stab wounds inside their first-floor apartment in the same building. 

All three were pronounced dead at the scene. 

NYPD Chief of Detectives Joseph Kenny revealed that the five-year-old was basically disemboweled by his half-brother.

Kenny said that Jayden - a scholarship student at SUNY Oswego - had told his own mother - while still covered in his victims' blood - that he was 'hearing voices' in the days leading up to the murder and believed his father and his father's girlfriend meant to harm him. 

'Later on, when he returned home, he stated to his mother again that he was hearing voices and that he thought that Mr. Rivera and Ms. Peralta were going to hurt him.'

Jayden initially fled the apartment after killing his victims but returned to attempt to violently pound their bodies with a kitchen pot, the New York Post reported.

He was checked into Westchester County Medical Center in Valhalla, where he allegedly confessed to the murders.

Jonathan Rivera and Peralta had broken up but were reconciling at the time of their deaths.

Rivera has two other daughters in Connecticut. Friends and relatives said he worked two jobs to make ends meet, including at Kayden's school. 

Hours after the grisly discovery was made, the former superintendent of the building fondly reminisced on his interactions with Kayden as he went to and from school.

'I play with him every day,' said Jose Torres. 'That's my little buddy there.'

Neighbor Paulette Williams said: 'I heard people talking about they heard loud fighting and arguing, and then it stopped — and that's when they found out they were dead,' she added.

Torres, 60, believes the family moved to the building about five years ago.

'They always go out together,' he said. 'I never had no problem with none of them.'

Dahan Ali owns a deli in the building and knows all the victims, said: 'I would always see her every morning at 7, 7:30 when I came she would take her son to school, with her son every morning.' 

People living in the building say the family kept to themselves and that they never saw any problems between the couple or their little boy.

Ms Ali continued: 'Lovely boy, very lovely -- saw home day before yesterday, he took a cookie, I said 'where is your father?' He said outside.'

The medical examiner has determined the cause of death as homicide. 

The investigation is ongoing and so far there are no suspects or motive.