MESQUITE, Texas — This story has been updated throughout 

A Mesquite school bus driver was arrested Tuesday on a charge of criminal solicitation of a minor to commit sexual assault, police said.

Ruben Castillo had been a bus driver for the Mesquite Independent School District for 11 years, according to police.

The investigation began when a student at Horn High School contacted the police and told them he received a call and several texts from Castillo during the summer break, according to a warrant.

The student told detectives at least one of those messages contained a solicitation to commit sexual assault.

Castillo later agreed to meet with detectives, who say the bus driver admitted to finding the student "sexy." 

He also allegedly admitted to calling the student and saying "'one thing' that would be viewed as inappropriate," the warrant says.

Detectives said the bus driver also said he contacted two other students over the break, but claimed he didn't say anything inappropriate to them.

Mesquite ISD said in a statement Tuesday that Castillo is no longer employed by the school district:

"Upon learning of the allegations regarding Mr. Castillo, Mesquite ISD acted swiftly to remove him from his position and terminate his employment with the district. These charges are very troubling, and we are sickened that a trusted employee attempted to victimize one of our students. While we are unaware of any other students who may have been impacted by Mr. Castillo’s actions, the district is cooperating fully with the police investigation."

Castillo was arrested at his home in Seagoville. Monday was the first day of school for Mesquite ISD.

The police department is asking any other victims to come forward. 

Bus driver accused of child sex assault

More coverage on WFAA: