Friends of the family and neighbors told CBS New York on Monday they're shaken up over the gruesome killings.
"We just want justice, man. What went down was just brutal. It just doesn't make sense," said Eusebio Baez, a close friend of one of the victims.
, has rocked communities from the Bronx to Washington Heights, leaving them the only option but to remember their beloved friends.
"Jonathan was the best dude ever, you know? A heart full of gold. The baby was full of joy, was so animated. His girlfriend was a good partner," Baez said.
It appeared to be a normal day for the family leading up to their murders. Surveillance video at a nearby bodega shows 33-year-old Hanoi Peralta at the counter.
"She bought something and then she leave like normal," 674 Neighborhood Grocery owner Dehan Ali said.
Baez, a close friend of 38-year-old victim Jonathan Rivera, said he was texting with him that night.
"They were on a date doing a paint and sip and it was all over social media. They looked happy. They were having a good time," Baez said.
But at around 6:40 a.m. on Sunday, police made the gruesome discovery of Rivera, Peralta and their 5-year-old son, Kayden, dead with stab wounds in the hallway and inside their apartment.
"It's a crazy scene. I never thought it would happen here and I've been living here for 11 years," neighbor Fernando Cruz said.
Cruz said he heard men yelling and fighting at around 11 p.m. that night.
"I heard like an altercation going on, like a lot of the noise, like a tussle, like somebody was fighting or something," Cruz said. "There was this last thing, where the man went ... ahh and it might have been the fatal blow and then it got quiet."
Friends said Rivera was a loving father and part of a large snowboarding community.
"You always felt safe around him. He was very considerate. He always made sure everyone around him was good. He was just full of love," Baez said.
As for 5-year-old Kayden, "He was such a good kid," Baez said, adding, "He had a bunch of different costumes. One day he was dress up as Spider-Man. One day he would dress up as Superman."
Police sources told CBS New York they believe the killings were carried out by a family member, and that it appeared to be a crime of passion.
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