A Texas teacher is accused of performing oral sex on a male student after the teen fell asleep.

The student learned of the alleged assault after seeing photos on his teacher's phone when he asked to use it to call his mother, according to court documents.

Manuel Alejandro Gamboa, 35, was arrested on Wednesday (24 January) on charges of improper relationship with a student and sexual assault.

The former substitute teacher at Delaney high School in Harris County appeared in court Friday (26 January).

Gamboa invited the 17-year-old male student to his Harris County home after plying the student with beer on 3 June, according to charging documents. "Complainant stated that he consumed several beers and became dizzy due to him not normally drinking," court papers stated.

The victim said he did not feel well and fell asleep on Gamboa's living room sofa bed. When he woke up, he found Gamboa next to him, he said. According to charging documents, the victim claimed he felt discomfort and minor pain while urinating.

When the victim asked to use Gamboa's mobile phone to call his mother, he noticed sexually explicit videos and photos of Gamboa performing oral sex on him while he slept without his permision.

Court documents said that a sexual assault exam performed at a hospital confirmed evidence of DNA on the victim that did not belong to him. The victim told investigators he viewed Gamboa as "a mentor" who helped him with his homework "due to him not knowing any English".

Gamboa is being held on $80,000 bond.

Spring Independent School District officials said that they immediately removed Gamboa from the district's substitute pool after learning of the allegations.

"The safety of our students is our highest priority," officials said in a statement to KHOU. "The criminal history and references of job applicants, including those who apply to serve as substitutes, are routinely checked before they are hired."