NEW HAVEN, Conn. — A jury voted Monday to impose the death penalty on a habitual criminal who took part in a home invasion in Cheshire, Conn., that left a woman and her two daughters dead, a crime of such inexplicable cruelty and randomness — the family was apparently chosen after being spotted in a shopping center parking lot — that it upended a debate about capital punishment.

For nearly two months, jurors learned every searing detail of the night and morning in July 2007 when two men armed only with a BB gun that looked like a real pistol burst into the colonial-style home of a successful doctor and put him and his family through an ordeal of beatings and sexual abuse that ended as flames tore through the house where the girls, still alive, had been strapped to their beds. Their mother had already been strangled.

Only the father — William Petit Jr., dazed and bloodied after being beaten with a baseball bat in his sleep — managed to escape.

He was in the front row Monday, slumped forward, as the defendant, Steven Hayes, sat motionless at the defense table. The court clerk announced, again and again, that jurors believed the crimes Hayes had committed required that he be put to death.

Jurors saw ‘images of depravity and horror’

In thanking the jurors, Judge Jon Blue of state Superior Court said they had been “exposed to images of depravity and horror no human being should have to see.”

The verdict came at the beginning of the fourth day of deliberations in the trial’s penalty phase. Only one person has been executed in Connecticut since 1960.

“This is a verdict for justice,” Petit said afterward. “The defendant faces far more serious punishment from the Lord than he can ever face from mankind.”

One juror, Herbert Gram of Madison, said the panel experienced little disagreement during deliberations.

“It was just so heinous, and just so over-the-top and so depraved,” he said of the crime. “Here’s a case where somebody doesn’t deserve to remain on the face of the earth.”

Second defendant

A second defendant, Joshua Komisarjevsky — whom Hayes’ defense lawyers portrayed as the leader to their client’s hapless, drug-addled follower — will be tried separately.

Jurors found that all six of the capital felony counts of which Hayes had been convicted Oct. 5 required a death sentence.

Hayes, a parolee when the crime occurred, has spent much of his adult life as a prisoner.

Blue set Dec. 2 as the date he will officially impose the sentence.