Bryan Anthony Rhoden, 23, was arrested in Georgia’s Chamblee city, more than 25 miles southeast of where the bodies were found, said Cobb County Police Chief Tim Cox at a press conference on Thursday.
He was charged on three counts of murder, three counts of aggravated assault and two counts of kidnapping,
Police believe Mr Rhoden to be the lone shooter in the triple-murder case and said Siller was shot in the head because he “witnessed an active crime” taking place.
On Saturday afternoon, Siller, who was the director of Pinetree Country Club in Cobb County, was found dead at the 10th hole of the golf course with a gunshot wound to his head.
The bodies of two other men – identified as Paul Pierson, 76 of Kansas and Henry Valdez, 46 of California – were found in a white Dodge Ram 3500 pick-up truck on the golf course.
Police said Siller was not a target of the shooter. “We definitely feel confident there was no relationship between the shooter and Siller,” Mr Cox said during the conference.
Siller was not playing when the crime occurred. He was shot dead when he approached the 10th hole to find what happened after a truck was found stuck in a sand trap. The shooter abandoned the truck after killing Siller and fled the spot on foot, reported news station WAGA-TV.
The truck, inside which the bodies of Pierson and Valdez were found with gunshot wounds, was registered to Pierson.
Several details of the case remain unclear. Police have not confirmed any possible link between the two other men, but said they were not affiliated with the country club.
It was also not clear what led police investigators to Mr Rhoden, according to WAGA-TV. Mr Rhoden’s name emerged a few days after the bodies were found at the golf course, but police did not elaborate how.
According to the TV network – citing online DeKalb County jail records – Mr Rhoden was arrested on the same day as the murder for unrelated charges, including for DUI, providing false ID and other traffic charges. He was, however, released on bond two days later, before being arrested again, according to jail records.
Siller, 46, was married and a father of two children ages six and seven, according to the Pinetree Country Club.
The 10th hole where the bodies were found will remain closed for play, even as the golf course was opened on Wednesday.
Erna, the sister of 46-year-old Valdez, the other victim, told The Daily Beast her brother was a loving son, brother, uncle, and friend.
“A lover of music, surfing, traveling, and made friends wherever he traveled to. His laugh could erupt a room and his big heart will be missed greatly,” she said.
The Georgia State Golf Association expressed condolences for Siller’s death in a tweet: "All of us at the GSGA are deeply saddened by the tragic events that occurred earlier today at Pinetree CC. Our thoughts and prayers are with Gene Siller’s family and friends.”