Bob Martin is trying to make sense of the senseless.

"It only takes a few moments. Just a few moments, and everything is gone."

Around 1:00 a.m. on Sunday, a fire broke out in Martin's daughter's mobile home off of Ganzer Lane in Millcreek and quickly spread.

Adam Keefe lives directly next door.

"It was chaotic, and obviously upsetting that this all happened," said Keefe. "By the time we notified everybody, smoke and flames were already coming out of the house. It was intense."

According to Martin, his daughter and her husband--both 57--made it out of the burning home. However, his grandson and his grandson's friend were killed. They were 19 and 20-years-old.

"It will probably take a while for it to really connect with me on this," said Martin. "It's not the first death in the family. My wife died first of a stroke and that took a toll on the whole family."

Marin says his daughter suffered from smoke inhalation and her husband from burns.

"It's a very sad situation that's happening," said Martin. "The two boys that didn't make it out. That's going to be felt on both sides."

According to Millcreek Police, a dog and a cat also perished in the fire.

Fire marshals are trying to determine an exact cause.