And members of the country club where Gene Siller was killed remain in the dark about why the killings happened, a friend of Siller's said Tuesday.

"This doesn't make any sense," Brian Katrek, a member of Pinetree Country Club in Kennesaw and an anchor of SiriusXM PGA Tour Radio, told CNN's "New Day."

"I think the reaction from members right now is still one of pretty profound shock."

Cobb County police said they were called to a report of a person shot around 2:20 p.m. Saturday and found Siller -- the club's director of golf -- shot in the head near the green of the course's 10th hole.

A truck was on the green, and officers found the bodies of two other men in the truck's bed -- both of whom also had been shot, police said.

One of the slain men was Paul Pierson, the registered owner of the Ram 3500, police said. The name of the other slain man was not released.

Police have said they're trying to determine what happened and have not released the name of a suspect.

Investigators told CNN they are asking residents to check their doorbell video for any clues.

Siller leaves behind a wife and two children

Siller, 41, leaves behind a wife and two children, ages 6 and 7, according to the Pinetree Country Club.

PGA of America President Jim Richerson also issued a statement: "We are truly heartbroken to hear about the senseless murder that took place yesterday at Pine Tree Country Club in Georgia that took the life of PGA member Gene Siller," the statement said. "PGA of America sends our thoughts, prayers and deepest sympathy to his family, club and the Georgia PGA Community."

Sebastian Schutte, a friend of Siller's, said the community was in shock.

"It didn't hit me until later that this happened at our country club," he told CNN on Monday. "I still can't believe it."

He said Siller was well-liked and "treated everyone with respect."

Siller's family set up a GoFundMe page to help with finances.