Two families are reeling after a heated argument turned deadly in Robertson County.
A father stepped in to protect his son before he was shot and killed.
Chris Helser was known as Chris the photographer. He took pictures of everyone who meant something to him.
"He's had a loss in his life too and he knew pictures are important because that's what you're going to have when they're gone," Nickie Humphrey, his girlfriend said.
Humphrey said he was her soulmate. A picture of their family now means the world to her.
"This is our only family picture we'll have," Humphrey said.
On Monday night, Robertson County deputies found Helser dead outside his home on Jack Teasley Road in Pleasant View.
"We tried to administer CPR. It's a terrible helpless feeling. It's what that was," Humphrey said.
The sheriff's office said 21-year-old Travis Presley shot and killed Helser.
After leaving the house, they said Presley called 911. Deputies found him down the road and arrested him.
"If I could talk to him, I would want to know what he was thinking that this is what he needed to do," Humphrey said.
Investigators said Presley drove to Helser's home with a gun to confront his 17-year-old son. They were co-workers.
The teen's dad stepped in to protect his son during an intense argument before he died.
"We're just devastated. There's not a better word to describe how we feel right now," Humphrey said.
The family didn't want to get into details about the argument because of the active investigation.
Presley's attorney did not want to comment about the case.
Funeral arrangements for Helser have been set for Sunday at 3 p.m. at Greenville United Methodist Church at 5892 Clarksville Pike in Joelton.