Armed with a sock that had a rock inside it, 17-year-old Cody Casey refused to leave the Rosemount home premises of the young man he believed liked the girl he'd asked to prom that morning.

The man's two younger brothers, Dakota Butler, 16, and Zachary Albert Butler-Martinez, 18, insisted their 19-year-old brother wasn't home, but Casey -- who had ridden his bike over after school Thursday -- didn't budge.

Butler went inside and grabbed a steak knife, then came back to ask Casey to leave again, according to a criminal complaint filed Monday.

Casey took out the sock with a rock inside it, and hit Butler in the head.

They fought in the driveway, and Butler stabbed Casey at least four times before Butler-Martinez pulled his angry brother and Casey apart, according to Dakota County Attorney James Backstrom.

"Dakota Butler went inside the home," said Backstrom, who is seeking to have Butler tried as an adult. "He could have called the police. He could have called his parents, he could have asked for help. ... Instead, he took a knife outside and after that, the confrontation escalated."

Butler, a junior at Rosemount High School, was charged in Dakota County juvenile court on Monday with second-degree murder. The case is believed to be the first homicide in the city's history.

Casey, a senior at the high school, got back on his bicycle, wobbled a block, told a passerby that he needed help, and fell onto a snow-covered boulevard between the street and sidewalk. He was pronounced dead of stab wounds at Regions Hospital in St. Paul.

Story is incomplete

According to Butler's attorney, Andrew Small, much of the story remains to be told.

"I can't tell you that we're going to be claiming self-defense, but I think there are some facts out there that would support that potential defense," he said.

Butler's next court appearance is scheduled for May 19. Small said that he is going to fight efforts to get him tried as an adult.

"He doesn't have any real criminal history to speak of. He is a kid that I think the juvenile justice system would be best served to rehabilitate, if it's determined that it's needed," Small said.

Butler-Martinez has been charged by summons with a lesser felony: Aiding an offender. According to the criminal complaint, he was afraid his brother would get in trouble, so he wiped down the knife and threw it in a sewer outside their home. He eventually told police where it was, after first denying he knew what had happened to it.

Backstrom said police found a "steak knife-like" knife, with a 6-inch blade and a serrated edge in the sewer. Butler-Martinez was released from jail on Friday, while Butler remains in Dakota County's secure juvenile facility in Hastings.

Casey had been dating Ariel Neally, 16, for about a month before he asked her to prom on Thursday, according to Neally's mother, April Rosendahl. Neally was just friends with Butler's 19-year-old brother, Rosendahl said, but Casey was jealous of the friendship and biked to his house Thursday afternoon.

Casey's family did not return calls to their house on Monday. On Saturday, his father, Roger Casey, told a reporter that he was not ready to talk about his son.

"I can't believe it's real," he said.

Rosemount High School Principal Greg Clausen said Monday that life was beginning to return to normal for the school's students, although he expected "more than 100" students to be excused from school this afternoon for Casey's funeral.

Memorial T-shirts

A group of students is also designing a T-shirt with Casey's picture on it, and plans to give the proceeds to Casey's family for a memorial.

"As a principal and part of the faculty, it's one of the most difficult things and one of the most emotional things that you have to experience," he said. "The reaction from students and the community, and the idea that one of your students is gone, it's something that you don't expect."

Funeral services for Casey are at 1 p.m. today at the Community of Hope Church, 14401 Biscayne Ave., Rosemount. Instead of flowers, memorials can be directed to the Cody Casey memorial fund at any TCF Bank in the metro area.

Emily Johns • 952-882-9056