The family of Australian baseballer Chris Lane are struggling with his "senseless" murder in Oklahoma, allegedly at the hands of three teenagers intent on a killing spree.
Mr Lane's father, Peter, says his son had given up a lot to follow his dreams to the US and now they would never be realised.
"It was just so senseless," he said in Melbourne on Monday.
"There wasn't anything he did or could have done."
Mr Lane, who grew up in Melbourne's north, was murdered on Friday afternoon after he left his girlfriend Sarah Harper's home for a jog in a quiet, upper-class area of the small city of Duncan.
Police allege the accused killers - aged 15, 16 and 17 - followed Mr Lane in a car, shot him in the back and sped off in a random drive-by, before heading to another house with plans to kill again.
One of the teenagers is believed to have written on Facebook: "Bang. Two drops in two hours."
The youths were arrested before they got to their intended second target.
Danny Ford, the chief of Oklahoma's Duncan Police Department, said there would have been more deaths if police hadn't caught them so quickly in a town that hasn't had a murder in five years.
"They wanted to be Billy Bob Badasses," Chief Ford told AAP.
"I think they were on a killing spree.
"I know everybody thinks there has to be a reason, but I've been in this business for 30 years and there doesn't have to be a reason with these kids."
The three teenagers are expected to be arraigned in a Duncan court on Tuesday AEST.
Mr Lane, 22, had been in the US on a baseball sports scholarship with East Central University (ECU) as the team's catcher.
Witnesses saw him stumble across the road and then go down on his knees before struggling to a drainage area at the side of the road.
A woman who came from a nearby house tried CPR while another woman who was in a car stopped and called 911, but he was pronounced dead about an hour later.
Mr Lane and his girlfriend of four years had only been back in the US for three days after visiting his family in Melbourne.
She paid tribute to him on Facebook, posting photos of their recent trip to Australia.
"This last adventure together I'll always cherish," Ms Harper wrote.
"The past 4 years have been the most amazing years of my life."
His parents and former teammates in Melbourne remembered a man who was motivated, happy and making plans for the future.
"He was just a kid on the cusp of making his life," his father said.
Police say the only information investigators had at the scene was that the killers had been in a black car with a white sticker.
About four hours later, a concerned parent called police to tell them several juveniles were coming over to kill their son.
Police scrambled to the address and found a black car with a white sticker in a nearby church car park, with the three teenagers in it.
The boys were arrested, with one allegedly confessing to Mr Lane's murder, Chief Ford said.
The boys did not have an apparent link to a gang or drugs.
Mr Lane's body is expected to be flown back to Australia later this week.
His former Essendon baseball club in Melbourne will hold a tribute game in his honour this weekend.
ECU also expressed its grief.
"We will do everything possible to support his family and teammates during this sad time," said the university's athletics director, Jeff Williams.
