RICHMOND, Texas -

Fort Bend County Sheriff Troy Nehls sat down with Local 2 Monday afternoon and discussed exclusive new information about a homicide investigation involving a 20-year-old who allegedly shot his own parents dead inside their home.

Ryan Walton was arrested Saturday afternoon on two counts of murder at the 2-M's Malt n' Burger on Avenue H in Rosenberg.

"He was cooperating with our investigators and during the course of the interview he did state that he killed his parents," Nehls said. "Over the next few days we'll continue to talk to Ryan and try to piece this together and figure out why he would have done this to his parents."

Nehls told Local 2 he is confident Walton acted alone.

"Ryan provided details of that crime scene that only he would have known, only the perpetrator would have known," Nehls said.

Prior to the slayings, Walton was last seen at his parent's home about four weeks ago.

Nehls said they have not recovered the murder weapon. Deputies impounded the BMW Walton was driving at the time of his arrest and they waiting on a warrant to go inside and search it.

"Hopefully we will be able to find the weapon inside the vehicle," Nehls said.