i'm meredith vieira. >> i'm matt lauer. this morning there has been a major break-through at that west virginia coal mine where at least 25 workers were killed in monday's explosion. >> that's right. after spending more than a day drilling ventilation holes overnight, officials determined the air was safe enough for rescuers to enter that mine. they are now in there searching for those four missing miners. we'll get the latest from the scene in just a moment. >>> also ahead, the latest on that situation aboard united airlines flight 663. it happened last night and led to some extremely tense moments. the flight was about 30 minutes outside of denver when a flight attendant smelled smoke as a passenger left the bathroom, when the man was confronted, he apparently made a joke about setting his shoes on fire. that's when authorities were put on high alert. fighter jets were raced to intercept the flight. we'll have more on what was a tense situation coming up in a couple of minutes. >>>...

we'll talk to his sister in a moment, but first nbc's lee cowan has the details. >> reporter: it's picture postcard perfect. how could anything go wrong here? but behind the picket fences of ft. bragg, california, lay one town's dark secret. >> i had no yesterday that our neighbor was the kind of guy that would rape kids. >> reporter: mindy used to live next door to a boy scout leader named darryl mcneal. she trusted mcneal, just like her brother, aaron vargas, trusted him. but last february, aaron, now an adult, drove to this remote trailer and shot mcneal point-blank with a pistol. was there ever a time that you looked at your brother as a murderer? >> no. when i look at aaron, i see a sad little boy that needs help. >> reporter: the crime was shocking for his family. not as shocking as his motive. aaron alleged mcneal had molested him for years, starting when he was just 11 and continued stalking him even after he became a parent.