Boston (AP)  -- A middle school teacher and high school coach pleaded not guilty Monday to charges he repeatedly sexually abused three young boys.

49-year old Robert Dacey, who was a drama teacher at the McDevitt Middle School and coached three sports at Waltham High School, was ordered held on $25,000 bail during his arraignment Monday in Waltham District Court. He faces two counts of child rape, two counts of child enticement and one count of indecent assault and battery. The judge ordered him kept on house arrest at the home of his sister, should he post bail.

Authorities say he repeatedly raped and assaulted one boy, who is now 21, at his Waltham home over the span of several years in the late 1990s, beginning when the boy was 14.

Dacey also is charged with sexually assaulting two other boys, both currently 15, at his home on several dates in 2005.

Prosecutors say Dacey met all three boys through his role as their drama teacher or coach.