The dean of students at St. Vincent de Paul High School in Petaluma was fired "for inappropriate behavior with a student," a spokeswoman for the Roman Catholic Diocese of Santa Rosa said Thursday.

Jeff Dvorak, 36, was dismissed Monday after serving as dean for about two years, St. Vincent principal John Walker said. As dean, Dvorak's primary job was maintaining discipline at the school.

Contacted at home in Petaluma, Dvorak said: "I've got nothing to say right now."

Petaluma police are talking to a female student at the school about whether she was 18 or younger when certain events took place, Capt. Dave Sears said. He declined to name the subjects of the investigation, which is ongoing.

Deirdre Frontczak, the diocese spokeswoman, said school and diocese officials believe "the student was 18 throughout the period of whatever was going on." She declined to elaborate on the allegations.

Walker said some students have asked for information about rumors circulating at the school and felt "a bit frustrated" that he has not been able to tell them more.

He said he consulted diocesan officials and then contacted police Tuesday to inform them of allegations but added that he "didn't think criminal conduct was involved."

Also Tuesday, Walker sent an e-mail to parents and others saying Dvorak was no longer employed at the school. Assistant Principal Robert Blasser assumed his duties.

Walker said Dvorak was hired after an "exhaustive" process of interviews and reference checks, conducted over the phone because Dvorak was then working at a school in England. He declined to name the school.

St. Vincent is a private Catholic school that employs lay teachers. The school has an enrollment of 395 and is under the supervision of the Diocese of Santa Rosa.