ZEPHYRHILLS — A Hillsborough County sheriff's deputy was arrested Monday and accused of having a sexual relationship with a 15-year-old girl.

Juan Ortega, 50, of Zephyrhills has worked as a detention deputy in Hillsborough since 2007 and has been suspended without pay pending the outcome of the investigation, authorities said. Pasco sheriff's spokesman Kevin Doll did not disclose how Ortega and the Zephyrhills High School student met, although Pasco County schools spokeswoman Summer Romagnoli said Ortega was a volunteer at the school. Ortega worked with band students, Romagnoli said.

The Pasco County Sheriff's Office report said the incidents between Ortega and the girl began in July. The report says Ortega picked the girl up from school during her lunch break several times and took her to his house in Zephyrhills. On two occasions, Ortega and the teen had sexual relations, the report says.

Another incident happened in a portable classroom unit on the Zephyrhills High School campus during band camp, a week before school started last fall, authorities said. Ortega also sent an email to the girl with a photo of his genitals, the report states.

Ortega admitted to the charges, the Pasco Sheriff's Office says.

Romagnoli said the backgrounds of all potential school volunteers are extensively checked and volunteers are never allowed to be alone with students. She said Ortega passed all of the background checks.

"We will make any modifications needed to ensure that our campuses are safe and our students are safe," Romagnoli said. She said the investigation is ongoing and the Pasco school system is cooperating fully with law enforcement.

Ortega is charged with transmission of material harmful to minors, two counts of lewd or lascivious battery and three counts of lewd and lascivious activity by a suspect older than 18 on a victim aged 12 to 16. He is being held at the Pasco jail in lieu of $55,000 bail.

Erin Sullivan can be reached at esullivan@tampabay.com or (727) 869-6229.