Teen Killed In Love Triangle With Teacher

A Chandler high school student involved in a love triangle with his 48-year-old math teacher was stabbed to death after the older woman's 20-year-old boyfriend found them together in her bedroom, police said Tuesday.

Sixto Balbuena, a Navy sailor on leave from California, found his girlfriend naked and the 18-year-old student in his boxer shorts in the woman's bedroom around 2:40 a.m. Friday, according to police reports and court documents.

Balbuena told police that Samuel Valdivia apologized to him before Balbuena began kicking, punching and throwing things at him, according to a police probable cause statement.

Police said Balbuena told them he "wanted to teach the victim a lesson," and stabbed him in the lower side with a kitchen knife, according to the court document. Valdivia later died at a hospital.

He also threw his girlfriend, Tamara Hofmann, to the floor, jumped on top of her and demanded to know how long she had been cheating on him, according to the document.

Balbuena said he never meant to kill Valdivia, telling police "the blade went in like going into butter" and that he just wanted to show Valdivia how much he hurt him by sleeping with Hofmann.

Police said Hofmann taught Valdivia math at El Dorado High School in Chandler and was also Balbuena's teacher when he attended Marcos de Niza High School in Tempe.

A call to both schools was not immediately returned Tuesday.

The was no phone number listed for Hofmann.

Balbuena is the one who called 911. He told officers he felt remorse for stabbing Valdivia after seeing him lying on the floor struggling to breath, police said.

Balbuena was arrested on a charge of second-degree murder after police found him covered in blood and told them about the killing. He remained jailed in lieu of $100,000 bond on Tuesday and did not yet have a lawyer.

The court document said Balbuena called Hofmann to tell her he was coming to visit from California. When he arrived at her house, she didn't answer the door or calls to her cellular phone.

That's when police say Balbuena told them he went in the unlocked door and heard noises from the bedroom. He told officers he thought something was wrong with Hofmann, so he grabbed a knife from the kitchen before discovering her with Valdivia, the court document said.

Police spokesman Sgt. Joe Favazzo said Hofmann is being investigated for potential misconduct.

A 2006 Chandler police report obtained by The Associated Press on Tuesday shows that police suspected Hofmann of having a sexual relationship with a then-17-year-old Balbuena.

After responding to a call about a suspicious vehicle, police found Hofmann and Balbuena sitting in a car around 1 a.m. on Nov. 1, 2006.

Hofmann told police Balbuena was a family friend and that his parents knew he was with her because they had all gone to a soccer game that night, according to the police report.

While interviewing Balbuena, who initially identified himself as his 21-year-old brother, police found that he had Hofmann's bra, according to the report.

"When questioned about Sixto (Balbuena) being in possession of her bra, Hofmann reported she had changed clothes in her car while at the soccer game because she was cold, and she told Sixto to put her clothes in the back of the car after she was done," according to the report. "Hofmann said she did not know Sixto had taken her bra."

When police called Balbuena's parents, they told them they did not know their son was with Hofmann. The parents also told police that Hofmann was Balbuena's math teacher and tutored him after school.

Both Hofmann and Balbuena denied being in a sexual relationship, and police closed the case.