OKLAHOMA CITY - An Australian man attending an Oklahoma college on a baseball scholarship was shot and killed over the weekend in what police described Monday as a random act of violence by three "bored" teenagers who decided to kill someone for the fun of it.

Christopher Lane, 22, of Melbourne, was found dead Friday in the town of Duncan, where his girlfriend lives. Three boys, ages 15, 16, and 17, are in custody and face a court appearance Tuesday afternoon.

A floral tribute rests on the home plate at the Essendon Baseball Club on August 20, 2013 in Melbourne, Australia. Australian Chris Lane was shot dead in Duncan, Oklahoma on Friday local time. Three teenage males have now been accused of the murder. [Photo/CFP]

Duncan Police Chief Danny Ford said Monday a woman called officers after she saw Lane stagger across the road and fall to the ground in the south-central Oklahoma town of about 24,000 residents. Ford said Lane, who was staying with his girlfriend and her family in Duncan, jogged past a home where the three boys were staying. He said the shooting appeared to be completely random.

Autopsy results are pending. Ford wouldn't say whether Lane was shot multiple times.

Ford said the 17-year-old has given a detailed confession to police, but that investigators have not been able to locate the murder weapon.

"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.'

"They followed him in the car to that area, shot him in the back and drove off," Ford said.

He said the district attorney is expected to file first-degree murder charges Tuesday, and all three will be arraigned at Stephens County District Court. It wasn't known if the three will be charged as adults or as juveniles.

Lane attended East Central University in Ada, about 85 miles (137 kilometers) 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 had an above-average baseball IQ. He was a tremendous defensive catcher and great communicator from behind the dish. ...

"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," Rosato said.

Ford told the Duncan Banner that police detained the three boys near a car and had retrieved a dismantled shotgun from the vehicle, but that Lane had been shot with another gun that had not yet been found. He said police have had "problems" with two of the three juveniles previously. He did not elaborate.

Lane's father, Peter Lane, told the Lawton Constitution that the family is devastated by the loss of a "sensational kid".