Arizona Teen Caught Up in Student-Teacher Love Triangle Killed

April 15, 2009— -- A love triangle between a high school teacher and two of her students turned deadly, police said, when one of her lovers allegedly stabbed the other after catching the pair naked in her home.

Sixto Balbuena, 20, a Navy sailor, is being held on a second-degree murder charge in the death of 18-year-old Samuel Valdivia. Both men were apparently lovers of 48-year-old high school math teacher Tamara Hofmann, who taught at El Dorado High School in Chandler, Ariz., where Valdivia was a senior, police said. Balbuena had also been a student of Hofmann's at another school, police added.

Valdivia's family was shocked by his killing, his older brother saying they had no idea he was having an affair with his teacher. The day he was killed, Valdivia was to have played in his first baseball game with the high school team, something he had been very much looking forward to.

"I don't know what happened," Julio Valdivia told ABCNews.com. "I don't have a clue."

According to a Chandler Police Department report, Balbuena was on leave from the Navy when he went to Hofmann's house around 2 a.m. on Friday. He told police that he entered the house after Hofmann, identified in the report as being his fiancée, did not pick up the phone when he called.

Police said Balbuena told them he heard a noise and, fearing for his fiancée's safety, grabbed a kitchen knife and headed upstairs where he saw Valdivia run into the bathroom. The report states that after forcing the bathroom door open and finding Valdivia in there with a nude Hofmann, he began kicking and punching the teen, later throwing objects at him, including a computer printer.

According to the report, Balbuena told police he didn't mean to kill Valdivia; he allegedly said he just wanted to teach him a lesson for sleeping with his fiancée.

When he stabbed Valdivia in the stomach with the kitchen knife, Balbuena reportedly told police, "the blade went in like going into butter."

Balbuena also told police, according to the report, that he threw Hofmann to the floor and demanded to know how long she'd been cheating on him, but he said he never got an answer. According to the report, Balbuena then called 911 and, feeling remorse for what had happened, waited for police to arrive.

Valdivia was pronounced dead at a local hospital.