By Greg Suskin

CHESTER COUNTY, S.C. (WSOC/CNN) - There are new details in the murder of a Chester County woman. Police say her own grandson is responsible.

After finding his wife's body, you can tell from the 911 call Mack Paul had no idea what deputies say his grandson had done.

[Operator]: "Is there anyone else there with you? Any kids or anything else going on?"

[Mack Paul]: "My grandson."

[Operator]: "Ok, go ahead, take your grandson and go somewhere safe, and just comfort your grandson."

Investigators say Clayton Watts didn't need comforting. They say he planned to pay Marqueas Buchanan and Shaderius Cohen $5,000 to kill both of his grandparents.

"He was pretty calm, no tears, just unemotional," said Sheriff Alex Underwood.

Watts and Buchanan were students at Chester High School. Deputies say the murder-for-hire plot first came up around Christmas.

"Mr. Watts picked up Buchanan and Cohen, provided them with handguns, and then went to the home at 1313 Williamsville Church Road and waited for his grandparents to get home," said Sheriff Underwood.

They were there for about an hour before Jimmie Paul came home, and she was shot three times with a .357 when she walked in the door. The .357, and a .9 mm belonged to the family.

Mack Paul survived because he walked in after Buchanan and Cohen ran. He found his wife on the kitchen floor.

[Operator]: "She's bleeding from her legs, she's bleeding from her stomach. I don't know if she's been shot."

When asked why he wanted the grandparents dead, Sheriff Underwood said it was because he didn't get his way.

"The grandparents required him to do the right thing. Go to school, be good at school, be respectful, be responsible," he said.

Sheriff Underwood says deputies found text messages between the three teens connecting them to this crime, but all three are cooperating, and admitted the whole thing.

They believe Cohen is the one who pulled the trigger.