(CNN) — As an Oklahoma town comes to grips with the apparent senseless killing of an Australian baseball player on their streets, one man is offering a possible motive.
"I don't think it was for fun. I don't think it was at random," James Johnson, whose call to police ended with the apprehension of three teens who are accused of killing Christopher Lane, told Australia-based Fairfax Media.
"I think it was a (gang) initiation," he said.
When Johnson called police, he didn't know about the killing of Lane, he told Fairfax Media, which owns the Sydney Morning Herald.
All he knew was that he got a call from his own son, who said the three teens -- James Edwards Jr., Chancey Luna and Michael Jones -- had threatened him because he refused to join a gang.
Johnson was working on his truck across the street, and as his son told him about the threat, he says, he saw the three teens arrive in front of the house in the town of Duncan.
He called police and told them about the threat and the boys at his house.
Police arrested the three and named them suspects in the killing of Lane, which had happened hours earlier.
Edwards' sister said Thursday that he did hang around some older men who were thought to be in a gang, but she said she didn't know about her brother actually being in a gang.
Edwards, 15, and Luna, 16, have been charged as adults with first-degree felony murder.
Jones, 17, faces charges of using a vehicle in the discharge of a weapon and accessory after the fact to murder in the first degree.
Police say Jones told them, "We were bored and didn't have anything to do, so we decided to kill somebody."
Lane's friends and family are being invited to a memorial game in his honor Sunday, and a donation page has been set up to raise money for a memorial fund in his name.
A former student and classmate at East Central University, where Lane was studying, described him as "a charming guy, genuinely good person, with great character and had a love for life."
"As cliched as it sounds, Chris was the kind of guy you want your sons to grow up to be and that you want your daughters to marry. It just breaks my heart knowing how much more he could have brought to this world as a husband, father, son, brother and friend," Sam Malchar said.
Richard Rhodes, a 37-year-old contractor who was working on a house near where the shooting happened, tried to save Lane's life by performing CPR, he told Fairfax Media.
"I was like this, telling him, 'buddy, stay with us; stay with us,' " Rhodes told Fairfax as he showed how he knelt next to the victim.
Rhodes was gasping for air, and soon the gasps stopped.
Rhodes and a woman together performed CPR until it became apparent that Lane had died, Fairfax reported.
CNN's Randi Kaye, Hilary Whiteman and Josh Levs contributed to this report.