LA QUINTA, Calif. -

A man who once served as a substitute teacher and part-time coach for the Desert Sands Unified School District was arrested and booked after a young girl claimed he sexually assaulted her.

Desert Sands Unified School District Asst. Superintendent of Personnel Sherry Johnstone confirms 29 year-old Daniel Patrick Armstrong taught over a dozen times on a substitute basis at La Quinta High School and in other classrooms throughout the district.

"We put safety first no matter what," said Johnstone. "If the police have an investigation, they lead and we respectfully follow. He is a former employee not a current."

Armstrong received a substitute teacher permit in February. It expires in March of 2012.

Armstrong resigned at the end of the school year, just months after the alleged sexual relationship ended.

"If someone were to come and want to work and there's an ongoing investigation, we freeze everything until the police investigate," Johnstone went on to say.

La Quinta police took the report on Aug. 3 from a 14-year-old girl who claimed a family acquaintance had sexually assaulted her several times in late March and early April, said Sgt. John Hignight.

The Indio Investigations Unit began their probe the same day, conducting interviews with the victim's friends and family.

On Thursday, police took Daniel Patrick Armstrong, 29, of La Quinta, into custody as he arrived home on the 80100 block of Avenue 52. He was booked on 25 counts of oral copulation, five counts of lewd act with a child, one count of sending harmful matter to a child and eight counts of digital penetration.

During the course of the investigation, detectives said Armstrong had worked in the past as a substitute teacher and part-time coach for the Desert Sands Unified School District, said Hignight.

Armstrong was a standout quarterback in the late 90's for the La Quinta Blackhawks football team. In 2000, he played a year at San Diego State University.

As recent as 2009, he helped his dad coach the varsity football team at La Quinta High School. His dad, Daniel Armstrong Sr. is the school's athletic director and head football coach.

Although no evidence has been uncovered indicating a connection between this victim and his school employment, detectives are asking that anyone with knowledge of any additional inappropriate contact involving him to contact them immediately.

If you have more information, call Investigator Mike Gaunt at the Sheriff's Indio Station at 760-863-8990.

Witnesses can also contact Coachella Valley Crimestoppers at 760-341-STOP. Informants can remain anonymous and may be eligible for a cash reward.