PHILADELPHIA (CBS) -- A body was found in a freezer at a South Philadelphia home Friday, police said. Now, authorities are working to find out what lead up to his death.

Friday afternoon, police tell CBS3 that a person of interest is in custody. They did not reveal the identity of the person.

Investigators were at the home on the 1200 block of Snyder Avenue around 6 a.m. trying to find out more information. 

Police say a father and son are the only ones who lived here and one of them may have been the victim.

Word of the grisly discovery caused a stir in the neighborhood Friday.

"This is a shock to the community, for people to wake up and see this," said Yusuf Mitchell, who lives nearby. "It's a Friday, Christmas coming up, and it's a bad way to start off the holidays."  

"It's pretty terrifying that stuff like this is going on," Ray Hassey, a neighbor, said.

Hessey was walking his dog early Friday morning when he heard a horrifying cry for help. 

"It was around 3:30, 4 in the morning, there was some screaming out in the street," he said.

Police say that scream came from inside this home, and officers believe it was a family who was doing a wellness check after not hearing from the family for a few days. 

Instead, the relative found a bloody mess inside and quickly called police. 

When officers arrived, they followed a trail of blood to a basement freezer. 

Investigators found blood in the home's basement and a man's body facedown, with a bag over his head in the freezer. A bloody knife was nearby, Philadelphia Police Chief Inspector Scott Small said. "It's a possibility this individual was stabbed to death."

Eyewitness News was there as investigators combed for clues.

The front and rear doors were checked by police. There was no sign of a forced entry and the property doesn't appear to be ransacked.