Todd Sousa, who ran Swim Venture, pleaded guilty last year to 16 felony counts of lewd acts upon a child and unlawful intercourse.
Prosecutors said Sousa repeatedly had sex with a 15-year-old over the course of a year. Recently, an informant told Orange County authorities that Sousa was also involved at that time with another alleged victim.
"Investigators were able to locate that victim, interviewed the victim. She stated that during that same time that he molested the other young female, she was also molested by the suspect," said Jim Amormino, a spokesman for the Orange County Sheriff's Department.
Sousa is behind bars on $200,000 bail and charged with rape and child molestation. He is expected to be in court Friday to answer to the new charges.
Until his first arrest, Sousa had been teaching and coaching swimming at various Orange County venues since the 1990s.
