LITTLETON, Colo. (AP) _ Less than three months before their carefully planned attack on Columbine High schoolmates, Dylan Klebold and Eric Harris were impressing a juvenile-court officer as bright young men with ``a great deal of potential.''

He wasn't the only one fooled: Neighbors and friends say they were reassured by the teens' middle-class backgrounds and quiet, ``utterly normal'' family lives.

Klebold, 17, and Harris, 18, were caught breaking into a van last year and entered a juvenile-court diversion program allowing them to clear their records. They finished the program in February, with flying colors.

``Eric is a very bright young man who is likely to succeed in life. He is intelligent enough to achieve lofty goals as long as he stays on task and remains motivated,'' a diversion officer wrote in Jefferson County District Court documents released Thursday. The officer's name was blacked out by the court.

Of Klebold, the officer wrote: ``Dylan has earned the right for an early termination. ... He is intelligent enough to make any dream a reality but he needs to understand hard work is part of it.''

Each teen completed 45 hours of community service, received counseling and wrote an apology letter. Harris received additional counseling in anger management, which he enjoyed, the officer wrote.

``These guys came in and put their best face on,'' said District Attorney Dave Thomas, the diversion officer's boss. ``Most of us in the system wish we were human lie-detectors, but we're not.''

The teens' middle-class upbringing also lulled adults into complacency _ even as some classmates grew alarmed at their bitter, vengeful tendencies.

At school, Klebold and Harris openly admired Hitler, hurled insults at minorities and conducted a running feud with the school's athletes. In the presence of adults, however, they were polite and friendly.

Klebold lived in a home worth nearly $400,000, a modernistic cedar-and-glass structure tucked between two huge stone formations on a rural road.

His father, Thomas Klebold, 52, is a former geophysicist who now runs a mortgage management business from his home. His mother, Susan, 50, has worked for the Colorado community-college system for years, helping disabled students gain access to education. Neighbors recall little about Dylan's older brother, Byron.

``We're all scratching our heads right now,'' said Michael Briand, who knows Susan Klebold from his work as a community-development consultant at Arapahoe Community College.

Briand said Thomas Klebold is known as a liberal who favors gun control. Susan Klebold is a sensitive listener.

``As far as I can tell, this family was utterly, utterly normal,'' Briand said. ``They did everything right. But somehow the pain and anger was too deep, and they didn't see it or couldn't reach it.''

Harris moved to Littleton in 1996 from Plattsburgh, N.Y., where his father, Wayne Harris, was an Air Force pilot. In Littleton, the family bought a two-story, $184,000 home on a quiet cul-de-sac. Wayne Harris got a job at a flight-safety business, and his wife, Katherine, went to work for a catering company, according to the juvenile-court documents.

Neighbors say Wayne and Katherine were quiet, sometimes waving across the fence while in the yard but making little effort to socialize. Eric's older brother, Kevin, played basketball with neighbors on trips home from college.

``They were pretty nice people, pretty quiet. They seemed to get along with everyone,'' said Matt Good, 16, who lives two doors away.

Former neighbors in Plattsburgh remember the Harrises as a solid, middle-class family with a likable young son. They were shocked to learn that Eric Harris had shot up a school.

``My mouth just dropped,'' former classmate Kyle Ross said. ``He was a typical kid. He didn't seem anything like what is portrayed on TV.''

The families were avoiding reporters, but both issued statements expressing sympathy for the victims, and Klebold's family wondered what went wrong: ``Like the rest of the country, we are struggling to understand why this happened.''

Briand said Klebold's parents grew hopeful in recent months that their son was starting to lose his fascination with the black clothes and rebellious ways of ``Goth'' culture.

But there are also signs that Klebold's father suspected his son was still a threat to himself and others.

On Tuesday, amid TV reports of gunmen in trench coats rampaging through Columbine High, the elder Klebold contacted authorities, suspecting his son was involved and offering his help as a mediator.

Officials said he was too late.