MURPHY: Can any of us imagine what's it's like being Dr. William Petit these last three years? Speaking with dignity and composure to courthouse reporters this week about the murder of his wife and two daughters. A crime as horrific in its details as any in recent memory.

Dr. PETIT: Over the last couple of weeks, I just kept keep trying to tell myself that good will -- good will overcome evil and we'll keep trying to do good things and try to refocus myself on the positive and stay away from the negative.

MURPHY: They were the family like so many we know in America : Jennifer , mom and wife, a school nurse ; Hayley , 17, on her way to Dartmouth in the fall; Michaela , 11, a TV cooking show fan; and William Petit , an admired doctor in their central Connecticut town of Cheshire . They seemed to suit their modest white colonial home on a quiet street. A home that on a Monday morning in July 2007 exploded in flames. Too hot for firefighters to knock down. Facts inside almost too ugly to understand. A picture later of a charred child's bed with ropes attached.

Unidentified Man: We do have three confirmed fatalities at this time. Two of them are female. A third, again, I don't want to speculate right now.

MURPHY: Mother and daughters dead.

Mr. GLASS: This is Charlie Manson -like crimes.

Ms. GRIFFIN: It's the burglar who breaks in the middle of the night at your home and attacks your family . I think it's everyone's worst nightmare.

MURPHY: Dr. Petit , bound by the feet and bleeding from a head wound, so grievously injured his next door neighbor didn't recognize the man crawling to him for help. The neighbor calling 911.

DAVE: I got Bill Petit here, who's hurt. My neighbor.

Unidentified 911 Operator: He's at your house?

DAVE: Yes, he's right here.

MURPHY: The murdered woman's sister as uncomprehending as anyone else.

Unidentified Woman #1: There's nobody on this earth that deserves what they had done to them.

MURPHY: It shouldn't happen to anyone, and certainly not in Cheshire , with its New England steepled church, a one-time farming town with roots going back to Colonial America . Bob Picozzi is a neighbor.

Mr. BOB PICOZZI: You would frequently see the whole family outside on a -- on a warm day. Bill loved to garden. Jennifer loved to garden.

And the two kids would be maybe helping them garden or maybe playing on the swing set.

Mr. PICOZZI: But no, they did everything together as a family .

MURPHY: Nice families in good homes, that's Cheshire . And then there was the smoldering ruin at 300 Sorghum Mill Drive , reminding everyone that the idea of being safe inside one's castle is only an illusion. It had been such a beautiful summer day, a Sunday. Dr. and Mrs. Petit and Michaela , the younger girl, went to church. Religious belief was a cornerstone of the family and the doctor patiently sat through Sunday school each week because Michaela had been reluctant to attend alone. Sue Trumbo 's a family friend from church.

Ms. SUE TRUMBO: We got to know them that way and eventually he was able to wean himself away, it took a long time, so that Michaela would stay without him.

MURPHY: Later on Sunday, Dr. Petit played golf with his dad. A day off from his practice as a diabetes specialist. Years back, Jennifer had been a nurse when they met while he was in medical school . Her weekend off was from duties as the school nurse at a local prep school , Cheshire Academy . Marilyn Bartoli , a parent there, recalls lonely boarding students regarding Ms. Petit as a substitute mom when TLC was needed.

Ms. MARILYN BARTOLI: I think people would actually try to be sick in order to be around her. She was that kind of woman .

MURPHY: For all her cheerful caregiving, Jennifer Hawke - Petit -- she used her maiden name -- was herself chronically ill, diagnosed with multiple sclerosis about age 40. Her friend Deb Hereld remembers getting the news.

Ms. DEB HERELD: Very unusual. She sounded choked up and she explained that she had just been diagnosed with MS. But then it was like she -- she kind of said, 'I'm just having my little breakdown now and then I'll just -- I'll be OK.' And she was!

MURPHY: Hayley , the older girl , made her mother's illness a passion and raised $54,000 for MS research. Hayley joined her mother and little sister that Sunday at the beach for a swim and a few hours of sun. She'd just graduated from the prestigious Miss Porter's School , where she was

an everything girl: co-captain of the basketball team, a driving oar on the crew.

Ms. HERELD: She was the respected girl. She was the girl who the kids would go to if they really wanted to know what was right to do.

MURPHY: Hayley would be following in her father's footsteps at Dartmouth in September. Like him, she was going to be a doctor. Now grown up, the one-time child who'd followed him on his hospital rounds. She was turning the MS fundraising work over to Michaela . Michaela , nicknamed " K.K. Rosebud ," was only 11 but showed signs of being every bit as tall as her rangy athletic sister. She'd inherited her mother's flair for music, and on a recent Sunday she'd performed her first flute solo before the congregation. K.K., with a shy smile so many people remembered later.

Ms. HERELD: It was as though she had a really good secret. She wasn't quite ready to share it with you.

MURPHY: Michaela was a budding foodie and vegetarian. After the beach that Sunday, Michaela was going to be the family chef. She'd be serving pasta with fresh summer tomatoes and her own special sauce.

Ms. GRIFFIN: The girls had called Dr. Petit to say, 'Would you pick up some corn or some vegetables at a farm stand on the way home ?'

MURPHY: Michaela and her mom needed to pick up a few other things at the store before dinner, so they swung by the Stop Shop . When they exited the supermarket, did they notice a man in a van watching them, someone taking special notice of the child? Mother and daughter drove home to Sorghum Mill Drive unaware that they were being followed. It had been such a pleasant Sunday.