A 57-year-old man was convicted today of sexually abusing a teenager over a span of seven months in 2015, the Los Angeles County District Attorney's Office announced.

At today's court appearance, Joseph Alan Kikuchi of Monterey Park pleaded no contest to all counts in case GA097357 in an open plea to the court: 12 felony counts of sexual penetration by foreign object, five felony counts of lewd act upon a child, one felony count of oral copulation of a person under 16 and five misdemeanor counts of child molesting.

The open plea means a sentence was not negotiated with the District Attorney's Office.

The defendant is scheduled to be sentenced Feb. 9 in Department T at the Los Angeles County Superior Court, Alhambra Branch.

Deputy District Attorney Rena Durrant, who prosecuted the case, said at the time of the crime Kikuchi was the girls' varsity basketball coach at Mark Keppel High School in Alhambra.

In July 2015, details of an inappropriate relationship between Kikuchi and a female student began circulating through the school, according to the prosecutor.

Two months later, a staff member at the school relayed the information to law enforcement, who then began an investigation into the crimes. Kikuchi was subsequently arrested and charged on Oct. 21, 2015.

The felony information cites the sexual abuse to have occurred between February and September 2015.

The case was investigated by the Alhambra Police Department.

Los Angeles County District Attorney / case GA097357 / January 11, 2017