Lane, who was visiting the town of Duncan, where his girlfriend and her family live, had passed a home where the boys were staying and that apparently led to him being gunned down at random, Police Chief Danny Ford said Monday. A 17-year-old in the group has given a detailed confession to police, and charges were expected Tuesday afternoon.
"They saw Christopher go by, and one of them said: 'There's our target,'" Ford said. "The boy who has talked to us said, 'We were bored and didn't have anything to do, so we decided to kill somebody.'"
He said they followed Lane, a student from Melbourne attending college on a baseball scholarship, in a car and shot him in the back before driving off.
Ford told the television station KOCO in Oklahoma City that one of the teens said they shot Lane for "the fun of it."
On Tuesday, Lane's girlfriend, Sarah Harper, laid a wooden cross at a memorial that popped up where Duncan was killed.
"We just thought we'd leave it," Harper said. "This is his final spot." Harper said she doesn't know who started the memorial, but it means a lot.
Australia's Herald Sun newspaper said Lane's former team, Essendon Baseball Club, would turn its Sunday game against the University of Melbourne into a tribute to Lane to raise money for the family. Roses and a baseball were placed on the home plate on Monday with the message, "A wonderful young man taken too soon. Why?"
Police said witnesses rushed to help Lane after hearing a shot Friday and seeing him stagger and collapse on a road in Duncan, a south-central Oklahoma town of about 24,000 residents.
"He was face down on the ground and he was shot in the back with a .22 revolver," builder Richard Rhodes told Australian broadcasters. "I had another lady stop and we tried CPR on him. And he passed away right here."
Harper said she and Lane had only returned to the United States from Australia last week.
Lane attended East Central University in Ada, about 85 miles west of Duncan. He started 14 games at catcher last year and was entering his senior year.
"He was an absolute joy to coach," baseball coach Dino Rosato said in a statement issued by the school. "Chris was an extremely well-respected teammate. ... He set a great example for all of his teammates, but more importantly for the younger players. He was a mature student-athlete who his teammates could look to for advice and support."
Peter Lane told Australian media there was no explanation for his son's death.
"It is heartless and to try to understand it is a short way to insanity," he said.
"You just have to gather together as a family and hold on," he told Sky News TV. "And that's what we're trying to do at the moment hold on."
Autopsy results on Lane were pending.