Police questioned a "person of interest" in connection to the three stabbing victims found dead inside an apartment building Sunday morning.

Police had been questioning a person of interest in the case. It was not immediately clear if that person was arrested.

According to the NYPD, Jonathan Rivera, 38, was found in the building's first floor hallway with a stab wound to his chest just after 6 a.m.

Shortly after that, the NYPD said Hanoi Peralta, 33, and Kayden Rivera, 5, were found dead inside the apartment and also had suffered stab wounds. Sources have confirmed that all three victims are family members.

Family members gathered at the family's home to mourn the loss of their loved ones at a growing memorial on East 136th Street. 

"I just came by today to leave flowers and candy and balloons," said Ana Diaz, Jonathan Rivera's mother. "I just hope tomorrow we have a better sense, they have somebody in mind."

On Monday, relatives of the victims told News 12 that they feared it was a son of the father of Jonathan Rivera who was responsible for the death of Rivera and his family. 

“Whoever did it, God will get to them, because they’re not getting away with that," said neighbor David Jones.