A Hooksett man was beaten to death just blocks from where his sister's high school graduation was happening, and officials don't think it was random.

Ryan Carlson, 20, was part of a fight between two groups of young men Thursday night at near Manchester Central High School's graduation at Verizon Wireless Arena. Presidential hopeful Hillary Rodham Clinton was the event's guest speaker.

"Essentially, someone beat him and left him for dead," said Glenda Blau, the fiance of Carlson's father.

State prosecutors said they were waiting for an autopsy before moving forward.

"It appears things started at the Verizon center," state homicide prosecutor Jeff Strelzin said. The fight then moved to near the Getaway Lounge, a Franklin Street bar. Strelzin said he didn't think anyone from the bar was involved.

"Based on what we know so far, it doesn't appear this was a random act," Strelzin said.

Blau said Carlson was hit at the base of the neck and fell in the nearby alley. He never regained consciousness and died at Massachusetts General Hospital.

Carlson had been living in Indiana and arrived in Manchester on Thursday for his sister's graduation.

Christine Carlson, however, was sick and did not attend her graduation. Blau said she thinks Carlson went to the arena not knowing his sister was at home.

"This was supposed to be such a marvelous weekend. We looked forward to this for a long while," Blau said. "And it turns into this walking nightmare. It's beyond strange. It's a difficult thing to get your mind around."