A high school basketball coach in Tucson, Arizona, was accused of having an inappropriate relationship with a minor, the Pima County Sheriff's Department said.

Senecca Turner, 37, was arrested Thursday on suspicion of engaging in misconduct with a 17-year-old female student, according to KVOA. Turner worked as a security guard and an assistant basketball coach at  Cienega High School. He faces charges of sexual conduct with a minor. 

Police said that detectives came across evidence during their investigation that led to reasonable grounds for Turner's arrest, according to The Associated Press. Investigators learned that there were signs of Turner sending explicit messages to the unidentified minor. 

In a letter obtained by Tuscon-based outlet KOLD, Cienega High School principal Nemer Hassey detailed Turner's apparent "disturbing" misconduct to parents. The principal wanted for parents to hear the news from him first, despite his belief that they would likely hear about the incident from news outlets.

"Yesterday, we received evidence of an inappropriate text exchange between Cienega security monitor, Senecca Turner, and a student," said Hassey. "Law enforcement was contacted and Mr. Turner was directed to leave campus immediately. This afternoon, Mr. Turner was arrested for one count of sexual misconduct with a minor." 

"You trust us with your children. We deeply honor that trust. Like you, we are shocked, angered and saddened by this situation. There are no excuses to be made. We will continue with a renewed vigilance and commitment to honor the trust you place in you," Hassey added. 

It's uncertain whether the child was a member of the school's basketball team.

At this time, Turner is being held at the Pima County Adult Detention Complex in Tucson. He is no longer employed at the high school.

A police investigation into the alleged complaint is still underway, with more information expected to surface soon.