SAN DIEGO -- A volunteer altar server and longtime San Diego Unified School District employee, who is accused of sexually assaulting a 14-year-old altar boy, pleaded not guilty Tuesday to a pair of child molestation charges.

San Diego police arrested Daniel "Mr. Danny" Herrera, 52, outside his Logan Heights home on Friday, SDPD sex-crimes Lt. Rick O'Hanlon said.

Herrera has held various jobs with the school district since 1985, most recently that of bus monitor for special-education students, the lieutenant said.

At his arraignment Tuesday, Herrera pleaded not guilty to charges of oral copulation by a person over 21 on a person under 16 and committing a lewd act on a child 14 or 15.

Judge David Szumowski ordered Herrera held on $100,000 bail pending a review hearing Friday. he also set May 29 readiness conference and June 2 preliminary hearing dates.

The defendant, who has no prior criminal record, faces three years and eight months in prison if convicted, said Deputy District Attorney Rachel Cano.

The prosecutor said Herrera worked as a volunteer organizing altar boy services at three San Diego-area Catholic churches -- Saint Joseph's Cathedral, Saint Jude's Shrine and Our Lady of Angels.

She said the alleged victim was an altar boy, and investigators are looking into whether additional altar boys may have had inappropriate contact with the defendant.

Cano urged anyone with information on Herrera to call the SDPD Sex Crimes Unit.

The alleged molestation occurred in late 2005, according to O'Hanlon. The boy did not report the purported crime until last October, at which time the San Diego Catholic Diocese notified police, O'Hanlon told reporters.

Herrera has been on paid leave since the accusation surfaced, school district spokesman Jack Brandais said.

He said the alleged victim is not an SDUSD student.

O'Hanlon said that for 20 years, Herrera managed youth dance groups called Floor Masters and Street Sensation.

The defendant worked at Whitman Elementary School in Clairemont as a bus monitor, yard supervisor and drama club coach for about 10 years, until last June, after which he was transferred to the post he worked until the molestation allegations came to light, according to Brandais.