While the vast majority of sudden deaths of babies are entirely innocent tragedies befalling loving parents, a troubling number of child murders have masqueraded, sometimes for years, as Sudden Infant Death Syndrome. Here's a look at some cases that have surfaced this year alone:

In October in Cherokee County, Okla., Matthew Ryan Guthrie was charged with first-degree murder for smothering his 2-month-old daughter, Cameron Guthrie.. The state medical examiner had ruled shortly after the Sept. 15, 2006 death that Sudden Infant Death Syndrome had killed her.

The body of a newborn infant girl was found April 5, 2006, inside a plastic garbage bag in Kitsap County, Wash. Authorities, who still seek the mother, named her "Dawn," because she had only seen the dawn of life. But after a prisoner in an Arkansas jail tipped police in April to information that indicated Guthrie had killed his baby, authorities began an investigation. On Oct. 1, Guthrie, 27, allegedly confessed to police that he had intentionally placed a sofa cushion on the baby as she lay on her back in a playpen.

Guthrie said Cameron's mother, Brandy Hurta, was there during the murder. He said they both had decided they "did not need the burden of a small child and decided to kill the baby," according to an account of the arrest affidavit in a local newspaper.

Hurta has not been charged.

In October in Parkersburg, W.Va., Charlene DeBerry, 19, was arrested on first-degree murder charges in the Sept. 12 death of her infant son, Michael. Prosecutors said DeBerry had admitted she wrapped a blanket around the 8-week-old infant's chest and squeezed it until he stopped crying.

But Deberry's attorney said the circumstances of the death could indicate little Michael died of SIDS, and said he was considering using that in defense of his client.

In September in Mansfield, Ohio, Ashley Ruckman, 17, was charged with aggravated murder in the Sept. 23 death of her boyfriend's son from another relationship, 2-month-old Colton Livingston-Speck.

The evening before, Ruckman had helped babysit Colton, who had recently been hospitalized for breathing problems. Colton's father, Ryan Livingston, found his lifeless body the next morning. Police initially pegged the death as a result of SIDS.

After more investigation, Colton was determined to have been smothered, police said. Ruckman has entered the juvenile-court equivalent of a not guilty plea.

In September in Onondaga County, N.Y., Shirley Winters was indicted by a grand jury on second-degree murder charges in the 1980 death of her 5-month-old-son, Ron Winters II, which initially had been blamed on SIDS.

Winters, 49, came under suspicion for Ron's death during the course of an inquiry into the November 2006 death of a 2-year-old boy who drowned while Winters was visiting his family in St. Lawrence County, N.Y.

That child, Ryan Rivers, was found dead in a nearly empty bathtub at his grandparents' home, where Winters was staying. Though she was trained in cardio-pulmonary resuscitation, Winters allegedly did not attempt to revive the boy, police said.

In August, Winters was indicted on second-degree murder, first-degree assault and endangering the welfare of a child in that death.

While investigating that case, police re-examined Ron's death and those of two of Winters' other children, who had died in a 1979 cabin fire.

All three bodies were exhumed. The autopsy determined Ron had been intentionally smothered and his mother was charged with killing him. The investigation continues into the two other deaths.

In June in Plattsmouth, Neb., police reopened an investigation into the July 2006 death of 3-month-old Grace Kidd, whose death had been ruled as SIDS.

Kory Kidd, Grace's father, came forward in June to say that his now-former wife, Michelle Shearer, had confessed to him shortly after Grace's death that she had suffocated the baby while she napped by covering her head in blankets.

Shearer, 23, also allegedly said she believed she would be happier if Grace were gone, but after the death realized she missed her child. She had left her husband a few days before Grace died.

Kidd, 27, said he stayed mum for a year because he essentially withdrew from life after Grace's death, which was followed by a divorce. He said he also felt partly to blame for losing his baby because he was not a better husband and father.
Shearer, who now lives in Mississippi, denied she killed Grace, but said she also carries guilt, which she said counselors have told her is normal.

Plattsmouth police said they have investigated the allegations but, because it is a "he-said, she-said" situation, the case is stalled. Kidd and his family have criticized the investigation as insufficiently thorough.

In April in Columbia, S.C., caregiver Andrea Person was charged with two counts of homicide by child abuse in the deaths of two children she had cared for in her home in the past decade. She also has been indicted on charges of killing an infant in April.

Person is accused of killing Elijah Brown, 1, in 2001. The child's cause of death was then officially classified as SIDS. But police now believe Person, 39, wrapped the boy in a heavy blanket and placed him under a heating vent, where he became dehydrated and died.

That death came three years after Zachary Ulengchong, 4 months, died in her care. The official cause of death in the 1998 case was pneumonia, but police said Person told them she had covered his nose and mouth until he stopped fussing, and found him lifeless when she later went to check on him.

Person first came under suspicion in those deaths in April, when Harris Walker, 2 months, died while Person was caring for him. While investigators were probing Harris' death they learned of the deaths of the first two babies.

Harris' mother said Person had called her that day to say the baby had been spitting up milk and had stopped breathing. The coroner ruled Harris died of "intentional asphyxiation."

Person has pleaded not guilty on all counts.

In April in Boone County, Mo., Nicole West, 25, was convicted of second-degree involuntary manslaughter and first-degree child endangerment in the death of her 6-month-old daughter, Deja West, on the day after Christmas, 2005.

West told police she had become frustrated by her baby's crying after a long day at relatives' homes and at a mall. She said she placed Deja facedown on a pillow, covered her entirely with a large blanket, closed the door and got high on wine, malt liquor, whiskey and marijuana while watching a movie.

About an hour and a half later, West checked on her baby and found her dead.

At her trial, prosecutors said Deja died from "homicide by smothering", and that West had been a reluctant mother, at best, sometimes wrapping the infant in a washrag instead of a diaper and leaving her alone in the car.

In West's defense, a former medical examiner from Jackson County, Mo., said he believed the child succumbed to SIDS, based on West's statement to him that she found the blanket around the baby's shoulders when she discovered Deja dead, thus indicating the infant had not died from smothering.

In May, a judge sentenced West to three months in jail.

In March in Maricopa County, Ariz., Amy Lynn Scott was found guilty of first-degree murder in the deaths of three Arizona infants for whom she had been a babysitter 18 years ago.

All three -- Shauna Cunnington, 2 months, of Phoenix; Zachary Mann, 8 months, of Scottsdale; and Jordan Whitmer, 4 months, of Tempe -- died within nine months of each other in 1989. Medical examiners ruled then that each baby died of SIDS.

Even so, an investigation continued and, in 2003, after a new detective dug into the case, the medical examiner's office conducted new autopsies and changed the cause of death for the two infant boys to intentional asphyxiation or suffocation. For Shauna, the medical examiner said he could not rule out suffocation.

The defense portrayed Scott as a woman troubled by depression. Though she would eventually have four children, Scott lost twins to miscarriage two months before the deaths of the three babies began.

In May, Scott, 39, was sentenced to three consecutive life terms in prison, with the possibility of parole in 25 years.