Survivor of home invasion attack faces suspects in court

LESTER HOLT, anchor: One of the most terrifying murder cases in memory is playing out in a Connecticut courtroom. On trial, a man accused of torturing and killing a mother and two daughters in their own home. Here's NBC's Jeff Rossen .

JEFF ROSSEN reporting: In this surveillance video, the final picture of Jennifer Hawke - Petit , less than an hour before her death. Prosecutors say Petit was at a local bank withdrawing $15,000 and calmly told the bank teller her entire family was being held hostage at home -- husband William , a prominent doctor, and their two kids, 11-year-old Michaela and 17-year-old Hayley . She said she needed the money for ransom, and one of the suspects was waiting in the parking lot. That's when the bank manager made this chilling call to 911.

Unidentified Woman: We have a lady who is in our bank right now who says that her husband and children are being held at their house, and if the police are told they will kill the children and the husband. She says they are being very nice. They have their faces covered. She is petrified.

ROSSEN: With good reason. Prosecutors say these two men, Steven Hayes and Joshua Komisarjevsky , were terrorizing the family, beating Dr. Petit with a baseball bat and tying him to this pole in the basement. His two daughters were tied to their beds upstairs.

Woman: They told her they wouldn't hurt anybody if she got back there with the money. She believes them.

ROSSEN: But prosecutors say once back home, Jennifer Petit was sexually assaulted and strangled. Then, officials say, the suspects set the house on fire. The mother and her two daughters were killed. Dr. William Petit escaped.

Dr. WILLIAM PETIT: Just tried to do the best I could for my family.

ROSSEN: This week he took the stand, describing in gripping detail his family's final moments. "They tied my hands at the wrists and my feet at the ankles," he told the jury. He heard one of the suspects say, "If he moves, put two bullets in him." Petit testified he could hear his wife and children being tortured in another section of the house. "I heard the moaning and thumps." How emotional was it for you to be on the stand today?

Dr. PETIT: Very emotional.

ROSSEN: In court, an unusual strategy by Steven Hayes ' defense attorney. In an effort to avoid the death penalty , he admits his client committed the crime, but also points the finger at police, saying officers could have done more to save the family. Cheshire police did respond to the Petit home, but never went inside. On the stand, the police captain testified they followed protocol, telling the jury, "If we had any indication of violence, I would have been the first one through the door." Prosecutors are pushing for the death penalty in a crime that was as brutal as William Petit appears strong. Jeff Rossen , NBC News, New York.