Petit Murderer Steven Hayes Tortured Little Brother and Is a 'Monster,' Letter Says

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The younger brother of convicted murderer Steven Hayes recounted in a letter read today in court, how the man now facing a death sentence burned him on the stove and held a gun to his head.

"Steven is what Steven is because he is a coward," Matthew Hayes wrote in the letter, which was read by a clerk. "As family of this monster we all have to live with this nightmare."

The jury is in the sentencing phase of the trial for Hayes, convicted of 16 felony counts relating the deaths of Connecticut mother Jennifer Hawke-Petit and her two daughters, Hayley, 17, and Michaela, 11, is winding down.

Closing arguments are expected Friday.

Dr. Eric Goldsmith told the jury today that it was Hayes' co-defendant, Joshua Komisarjevsky, that came up with the idea to rob a house in well-to-do Cheshire, because he'd done it before and that the gruesome turn of events in July 2007 wasn't in the original plan.

Hayes, he said, didn't know ahead of time that the home invasion would involve rape, murder and a fire to destroy the evidence.

And when Hayes worried about the DNA evidence that would be left at the scene, Komisarjevsky allegedly shot back, "fire kills everything," Goldsmith testified.

Hayes' defense has sought from the beginning of the trial to portray Komisarjevsky as the ringleader and Hayes as a hapless follower, in an attempt to spare him the death penalty.

Komisarjevsky, Goldsmith testified, told Hayes during the invasion that he'd already gotten DNA on one of the girls so they'd have to kill them both and urged Hayes to get his hands dirty.

Goldsmith's testimony today also revealed Hayes had sex with Hawke-Petit after he strangled her and that Komisarjevsky told Hayes that Dr. William Petit -- the sole survivor of the home invasion -- had died. Petit had been bound and badly beaten, but managed to escape to a neighbor's house and call for help.

The jury also heard an excerpt from a note Hayes wrote. It was signed "Edicius," or "suicide" written backward.

In the note, Hayes wrote that he wanted to die and though he said was not a monster like his co-defendant, he was a coward.

Goldsmith said Hayes has also been having nightmares of his young son burning.

The psychiatrist said that while Komisarjevsky may be a psychopath, Hayes was not. The doctor said he'd diagnosed Hayes as having adjustment disorder and anti-social personality disorder.

Defense witnesses have accounted for the vast majority of the jury's time in the sentencing phase, now in its second week. The prosecution rested the first day after calling a clerk to read a list of Hayes' convictions.

Defense Claims Steve Hayes Tried to Kill Himself Ahead of Petit Murders

Last week, Yale University Professor Dr. Paul Amble, who conducted a four-hour evaluation of Hayes earlier this year, testified that the defendant has made multiple attempts to commit suicide while incarcerated, as recently as August of this year.

Amble told the court that Hayes tried to kill himself "several times" prior to the Petit murders, and admitted to wanting to die after the Petit triple murder as well.

"[Hayes] described his persistent desire to die were because of his feelings of guilt, remorse and his condition of confinement," said Amble.

Since entering the MacDougall-Walker Correctional Institution, Hayes has attempted to overdose on a variety of pills. In October 2007, prison authorities found 20 pills that Hayes had hoarded in his cell and in January 2009 puncture wounds on his left forearm were spotted.

In January, Hayes "ingested a toxic level of thorazine," an anti-psychotic drug that Amble testified Hayes was not prescribed.

In August, just a month before his trial was slated to begin, Hayes tried to overdose on Ibuprofen, according to Amble.

Hayes told Amble that he often fantasized about killing himself, and even thought about sticking his head in the toilet in his cell and doing a back flip, presumably to break his neck.

Entering prison at 200 lbs, Hayes has since lost 70 lbs, in part because of his paranoia that the prison staff was "contaminating his food."

The jury has also heard wrenching journal entries by Joshua Komisarjevsky, who is scheduled to stand trial next year.

The dramatic readings included details of the last minutes of the lives of Jennifer Hawke-Petit and her two daughters, Hayley, 17, and Michaela, 11.

"Hayley is a fighter. She continually tried time and time again to free herself," he wrote. "Michaela was calm. Mrs. Petit's courage was, is, to be respected. She could have stayed inside the bank where she was safe."

Click here to read excerpts from Joshua Komisarjevsky's journal

Joshua Komisarjevsky's Musings on the Petit Murders Heard in Hayes' Sentencing

He also railed against the sole survivor of the Cheshire, Conn., attack, Dr. William Petit.

"Mr. Petit is a coward, he ran away when he felt his own life was threatened," Komisarjevsky wrote. "Time and time again I gave him the chance to save his family."

Dr. William Petit, who has attended every day of the court hearings, sat stoically through the testimony.

"I really don't want to dignify the ravings of a sociopath," he said outside the court that day.

Criminal defense attorney and former prosecutor Rikki Klieman said Komisarjevsky's cruel words toward the Petit patriarch will likely only strengthen the jury's sympathy for William Petit, the man they saw sitting in court every day of Hayes' trial as the murders and the rape of his wife and youngest daughter were recounted in chilling detail.

"I think it may backfire on the defense," she said.

"It all spills over on Steven Hayes. They are both depraved," said Klieman, who is not involved in the trial but has been following the case. "I think it's a high-risk game, and the roll of the dice may not go their way."

"This," she said of the 2007 crimes against the Petit family," is the worst of the worst."

The judge allowed Hayes' defense attorneys to present 43 pages of Komisarjevsky's letters and diary to help the jury determine the culpability of each man and their "relative evil."

"I'm not an angel," Komisarjevsky wrote. "I've never claimed to be. The scars on my soul have forever defined me as different than others."

Komisarjevsky said that he "resented" the implication that he raped Michaela and wrote that he had "spared her that degree of demoralization." Admitting that he did in fact sexually assault her, Komisarjevsky wrote, "In a vulgar display of power, I ejaculated onto her."

"As for why? It was the accumulation of years of pent up aggression," he wrote.

Komisarjevsky admits in the journal to taking photos of Michaela after the assault, images he wrote that he planned to use to blackmail her parents.

"What I was not prepared for was my demons getting the better of me," he wrote.

ABC News' Kaitlyn Folmer and Emily Friedman contributed to this report.