Updated

Ignoring his younger brother's plea of "Andrew, stop," a 17-year-old who told authorities he identified with a television serial killer strangled the boy, dragged the body to his car and drove to see his girlfriend, an Indiana prosecutor said Thursday.

Andrew Conley of Rising Sun was calm and showed no remorse or emotion as he described strangling 10-year-old Conner Conley as the two wrestled Sunday, a probable cause affidavit said. Conley told investigators he dumped his brother's body near a park in the Ohio River community about 90 miles southeast of Indianapolis.

"Sometimes people are just evil," Dearborn-Ohio County Prosecutor Aaron Negangard said. "This is an evil child."

Prosecutors filed preliminary charges of murder against Conley along with a supporting affidavit Thursday. Conley is being charged as an adult and will appear Friday in court, Negangard said.

Conley's family did not immediately return messages for comment Thursday. Negangard said Conley had an attorney but none was listed in the affidavit.

The teen told investigators he had had fantasies about killing someone since he was in eighth grade, including cutting somebody's throat, and felt "just like" the serial killer Dexter on the Showtime television series of the same name. He said killing his brother satisfied a craving like a hamburger satisfied hunger.

"Like I had to ... like when people have something like they are hungry and there is a hamburger sitting there and they knew they had to have it and I was sitting there and it just happened," Conley told investigators in the affidavit.

The slaying comes six weeks after 15-year-old Alyssa Bustamante told Missouri authorities she strangled, stabbed and cut a 9-year-old neighbor's throat because she wanted to know what it was like to kill someone.

The affidavit in Conley's case described him killing his brother before visiting his girlfriend and other friends. It said:

The two brothers were wrestling while their parents were at work. Conley put Conner in a headlock, causing the younger boy to pass out and fall to the floor. Conley dragged Conner to kitchen, put on a pair of gloves and choked the younger boy for about 20 minutes until he noticed blood flowing from Conner's nose and mouth.

He told investigators the child's last words were "Andrew, stop."

Conley put a plastic bag over his brother's head, secured it with black electrical tape, and dragged the body by its feet down steps to the basement and then from the home to his car. Conley struck Conner's head on the ground several times before putting the body in the trunk of the car.

With the body still in the trunk, Conley drove to his girlfriend's house and gave her a sweetheart ring. She told investigators Conley "seemed happy, more happy than she had seen him in a while."

Negangard said he will consider seeking the maximum prison term of life without parole. Conley's age makes him ineligible for the death penalty.

"I believe Andrew Conley is a dangerous person, and that's why we'll be considering the maximum penalty that we can impose," Negangard said.

Conley also told investigators that on the morning of Conner's death, he stood over his sleeping father with a knife and thought about killing him. Conley went to police Sunday night, admitted killing Conner and told investigators where to find the body.

The teen had no juvenile record and his teachers considered him a good student, Negangard said.

"This kid, Conner, was a good kid, and Andrew was an A and B student," he said. "This comes as a shock to the community."

Conley has been held at the Juvenile Detention Center in Lawrenceburg but was to be moved Thursday night to the Switzerland County Jail in Vevay.