Los Angeles (CNN) A man entrusted with helping the victims of sex crimes get justice has been arrested on suspicion of rape of a teenage girl while he was on duty, the Los Angeles Sheriff's Department said Tuesday.

Deputy Neil Kimball, a 45-year-old sex crimes investigator, is also accused of preventing or dissuading a witness from testifying, a felony, according to a statement from the department.

Michael Schwartz, a chief assistant district attorney in Ventura County, where the charges were being filed, said the rape charge carries a special allegation of tying or binding the victim. Schwartz said the alleged victim was 14 or 15 when the incident occurred and is 16 now.

Deputy Wally Bracks with the Los Angeles County Sheriff's Department said they believe the girl was 14.

It could not be immediately determined whether Kimball has an attorney.

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