The crazed Brooklyn man accused of murdering his grandfather with a machete and injuring two family members — including his 4-year-old sister — allegedly confessed to the heinous attack, new court papers reveal.

“I did what I did and there is nothing to talk about,” Dayquan Dubose told NYPD Detective Lukasz Organistka of the Jan. 3 slaying, according to a criminal complaint.

After 5 p.m., Dubose, 22, allegedly got into a fight with his family members in an apartment on Putnam Avenue in Bedford-Stuyvesant.

During the rampage, he first slashed the little girl in the hip, then turned his rage on his 79-year-old grandfather, James Dubose Sr., and stabbed him in the stomach, court papers allege. His brother-in-law Thomas Deese, 49, tried to wrestle the machete from Dubose, who then sliced Deese’s finger.

Dubose wasn’t supposed to be anywhere near his grandfather due to an order of protection from a prior case, court records show.

The alleged machete-wielding killer was arraigned early Tuesday in Brooklyn Criminal Court on charges of second-degree murder, criminal contempt, endangering the welfare of a child, assault and criminal possession of a weapon.

He was ordered held without bail.