(CNN) -- One of the Oklahoma teenagers accused of killing 23-year-old Australian Christopher Lane had previously posted images online showing himself posing with guns and wads of cash.
And three days before what police call the indiscriminate shooting, the suspect, 15-year-old James Edwards Jr., tweeted, "With my n****s when it's time to start taken life's."
Back in April, he tweeted, "90% of white ppl (people) are nasty. #HATE THEM."
Police in the town of Duncan have charged Edwards and Chancey Luna, 16, as adults with felony murder in the first degree, said Kaylee Chandler, a Stephens County court clerk.
Michael Jones, their alleged 17-year-old driver, faces two charges: use of a vehicle in the discharge of a weapon and accessory after the fact to murder in the first degree.
A judge set bond at $1 million for Jones, while no bond was set for Edwards and Luna, Chandler said.
Police say it was Jones who ultimately told them, "We were bored and didn't have anything to do, so we decided to kill somebody."
Lane was a promising young athlete, living his dream of studying in the United States on a baseball scholarship.
The people of Duncan, an affluent town of less than 25,000 people, welcomed him.
Lane had gone out for a jog, just at the time the teens had decided to find someone to kill, police say.
They drove their car behind him and opened fire, hitting him once in the back, authorities say.
He staggered across the road and fell to his knees, then managed to get up and take a few more steps before collapsing for good.
A woman who saw him struggling called 911. As she waited for an ambulance, the young man started to turn blue.
"If you don't hurry, he's gone," the woman warned.
But it was too late. The ambulance couldn't save Lane. He was pronounced dead at a hospital.
He was "the most amazing person I've ever met," his girlfriend, Sarah Harper, told CNN's "AC360" on Wednesday. "He was the most genuine and kind-hearted guy and would do anything for anybody at any time and ... made everyone feel special."
"There is no way to describe what happened," she said. "It's the hardest thing you could ever imagine happening. ...There is still a lot of shock and disbelief, and a lot of anger and sadness."
"You can't make sense of it," she added. "It's just -- so surreal that anybody could do something like this."
Immediately after the shooting, witnesses gave police a general description of a black car. Security footage from a nearby Mexican restaurant showed what could have been the car. But hours passed with no sign of whether there would be another killing.
Then, four hours after the shooting, a man called police, saying he could see three juveniles with guns -- and they apparently want to kill someone, said Duncan police Chief Danny Ford.
Officers responded to a home and found the car in a church parking lot across the street from the caller's house. The suspects were inside, and they provided enough information to be arrested.
Two days later, Edwards offered up details of the case, police said. The teens had been inside a house when Lane ran by, and the group decided he'd be the target -- to cure their boredom, Ford says.
"It is another example of murder mayhem on Main Street," former Australian Deputy Prime Minister Tim Fischer told CNN's Piers Morgan.
"People thinking of going to the U.S.A. for business or tourist trips should think carefully about it, given the statistical fact you are 15 times more likely to be shot dead in the U.S.A. than in Australia, per capita."
Former Australian deputy prime minister: 'There is deep-seated anger this time'
One Australian newspaper, under mug shots of the three suspects, ran the headline: "Faces of Evil: The teens American police say shot our star."
A Facebook page set up in Lane's honor, R.I.P Christopher Lane, had more than 67,000 followers by Thursday morning, with posts describing his slaying as senseless and tragic.
Lane grew up in Oak Park, a northern suburb of Melbourne in the southern state of Victoria. He showed sporting talent early on and started playing T-ball, a children's version of baseball, at age 7, according to Essendon Baseball Club president Tony Cornish.
"It's shocked our world. The baseball community in Australia is a tight-knit group. Most baseballers know most baseballers, and everyone's shattered," he said.
Cornish said Lane was a "very good athlete" who could have played Australian Rules football but chose baseball because it offered him the chance of a college education in America.
"If it didn't work out, he could have come back to Australia with an education and also been a much better baseballer. He would have been an elite player in Australia and at our club. That's the type of kid he is -- he created a 'win- win,' in a way, for himself," he said.
Harper said Lane loved to travel and loved the competitiveness of baseball.
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.
Harper visited the scene of Lane's death Tuesday. It's a grassy curb on a suburban street where flowers have been placed with messages of regret and condolence.
"I'm going to miss him forever. But I'm really glad that I got the four years with him," Harper told reporters. She and her family will travel to Melbourne for Lane's funeral on a date still to be set.
Lane's distraught father, Peter, told the media: "He's left his mark as we know, and you know there's not going to be any good come out of this, because it was just so senseless."
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.
The shooting took place one day before the three suspects were due to return to school.
Security was tightened around the Duncan School District after anonymous phone threats were made to Duncan High School.
Schools opened as normal Wednesday, but students were not allowed to leave for lunch and parents were being told they could keep their children at home if they wished.