Chief Dep. Geoff Dean said in a written statement last week that he's been asked by Sheriff Bob Brooks to step down from his position with the Ventura County Sheriff's Department.

Top officials wouldn't say why Dean was asked to vacate his post as one of the county's four chief deputies.

"The sheriff has advised me that he no longer wants me to serve as one of his chief deputies," Dean said in the written statement. "I am exercising my rights to return to the rank of . . . commander."

Dean is currently on administrative leave, said Chief Dep. Mark Ball.

Ball said Dean's departure from his post is a personnel matter and he wouldn't comment. Ball said, "It is under review." When asked to comment, Brooks wouldn't elaborate.

Dean, a 51-year-old Camarillo resident, has been with the department for more than 30 years. He's been a chief deputy for nearly six years.

As one of the chief deputies to Brooks, Dean was in charge of patrol and field operations, ongoing review of crime statistics and officer performances, and general investigations except for homicides.

In February, he was recognized as Public Servant of the Year by the Camarillo Chamber of Commerce.

A graduate of Simi Valley High School in 1974, Dean also worked in the sheriff 's department's special enforcement detail, including 10 years on the SWAT team. He also spent a tour working in the county jail.

While a deputy, he has patrolled the streets of Thousand Oaks, Moorpark and the unincorporated areas surrounding Simi Valley.

Dean was named lieutenant and served as the manager of the Thousand Oaks Traffic Bureau in 1989 and has also served as chief of police in Moorpark.

In 1996, Dean worked with the sheriff's crime suppression unit, an assignment he said he considered one of his most memorable postings. The unit handled gang violence and paid special attention to particular problems throughout the county.

"I have been honored to serve the county for 30 wonderful years and have appreciated the opportunity to serve on many boards and committees throughout the area," Dean said. "My family and I are overwhelmed by the tremendous show of support that community leaders, colleagues and friends have shown during this time."

Dean said he looked forward to "returning very soon to a job that I love."