LINCOLNTON Police are supposed to investigate quickly when a baby dies, but in North Carolina there's no guarantee of that.

On the night 3-month-old Aidan Christopher Stewart stopped breathing at his baby sitter's house, authorities in this small town failed to respond. A sheriff's deputy received a 4:30 a.m. phone call at home about Aidan.

Then he went back to sleep.

Two years later, Aidan's family says many questions remain unanswered, even though the Lincoln County Sheriff's Office has closed the case without charges: Did Aidan suffocate while sleeping? Did his baby sitter pay close enough attention to him? Why did police take so long to investigate?

"We can't have any closure," said Sharon Lingle, Aidan's grandmother.

N.C. Chief Medical Examiner Dr. Deborah Radisch said last month that her office had reviewed Aidan's autopsy results at his family's request. The agency said it would stand by its original diagnosis of sudden infant death syndrome, a natural and unpreventable condition that kills babies younger than 1.

But autopsy records and interviews show the case does not meet the standard that most medical examiners across the country use to diagnose SIDS.

Medical examiners are supposed to classify deaths as SIDS only after a thorough death scene investigation has helped rule out all other causes.

In Aidan's case, relatives said several days passed before police went inside the house where he died to search for clues and interview a witness. A department official says the investigation started sooner but acknowledges the death scene was probably compromised before a detective arrived, meaning potential evidence could have been lost or disturbed.

Aidan died after he was found face-down in a bed, raising the possibility he suffocated from an unsafe sleep position or bedding.

A recent Observer investigation found that a growing number of medical examiners around the country say suffocation - usually unintentional - is more common among babies than previously believed. The newspaper found that in North Carolina, two-thirds of SIDS autopsies list risks that suggest suffocation was possible.

North Carolina's top child death investigator, Lisa Mayhew, says most child death investigations are competent and thorough.

But state reports and interviews show Aidan's death reflects a longstanding problem: Not all police agencies consistently conduct thorough investigations, secure crime scenes or interview witnesses.

"There is always going to be a problem with consistency," Mayhew said.

No one knows how often police fail to properly investigate child deaths. The lapses in Aidan's case surfaced only when the family contacted the Observer after reading its investigation.

A 911 call after midnight

It was shortly after midnight on July 13, 2008, when 911 got the call. A baby had stopped breathing at a house in Lincolnton, about 37 miles northwest of Charlotte.

Dispatch informed paramedics, fire and police. A short time later, authorities say, paramedics arrived at the home to try to resuscitate the baby, but a sheriff's deputy on patrol told Dispatch he did not plan to go there. Paramedics took Aidan to the hospital, where he was pronounced dead less than an hour later.

After Jeff Paysour, a county medical examiner at Carolinas Medical Center-Lincoln, viewed the body, officials say he called another deputy, Don Mauldin, who was on call that night.

Paysour said he had not examined many infants but was concerned Aidan had an enlarged rectum, Mauldin told the Observer in an interview. Aidan's family gave a similar account when they described what Paysour told them.

An enlarged rectum is sometimes believed to be a sign children have suffered sexual abuse.

But Paysour said he did not believe a crime took place, Mauldin said. There were no tears, scars or bruises, which are indications sexual abuse could have taken place, Mauldin said.

A complete autopsy later led a forensic pathologist to the same conclusion. Radisch, the chief medical examiner, released a written statement to the Observer that said an enlarged rectum is common after death because of sphincter muscle relaxation. The condition is frequently misinterpreted as a sign of sexual abuse, Radisch said.

Paysour did not return phone calls seeking comment.

Mauldin said he listened to Paysour and decided he did not need to go to the death scene.

"There's no evidence of a crime," he said. "Why would you need the police?"

Mauldin said Lincoln County deputies at the time were not required to respond to all infant deaths. The department changed the policy after Aidan's family questioned the investigation, Mauldin said.

Guidelines for infant deaths

The state Office of the Chief Medical Examiner asks police to assume each infant death is a homicide until an investigation unearths another cause, said Mayhew, the child death investigator and police trainer for the agency.

"I teach that all child deaths regardless of circumstances are treated the same," Mayhew said. "We see too many mistakes, especially with the babies about them looking natural, or looking like a SIDS, when they are actually a homicide. Or marks or postmortem findings misinterpreted as trauma when it is not and parents being unfairly treated or accused."

The N.C. Justice Academy, which provides specialized training to law enforcement, teaches officers to treat all deaths of children and adults as homicides until an investigation finds another cause, said Noelle Talley, a spokeswoman for the N.C. Department of Justice.

Talley cited material from the courses that reads: "You may have a suspicion that the death is natural, accidental or suicidal, however you cannot allow the scene to be contaminated or required investigative steps neglected. This approach will eliminate many of the fundamental errors that can occur during a death investigation that are often difficult if not impossible to overcome later on."

Lincoln County Sgt. Lee Keller said his department handles all deaths with equal urgency. He disagreed with Mauldin, saying the department has always responded to all reported deaths.

Asked if a deputy should have immediately gone to the scene when Aidan died, Keller said he isn't bothered Mauldin went back to sleep.

The baby had been dead for hours by time the medical examiner called Mauldin, which means the death scene was probably already contaminated, he said.

"From everything I've read, it was handled properly," Keller said.

Circumstances unknown

The night Aidan died was the first time his mother had left him with a baby sitter.

Police identified the baby sitter as Leonard George Hawkins, a former assistant principal and teacher in the Lincoln County Schools. They said he was baby-sitting Aidan and a 1-year-old baby at his home that night.

Hawkins told police that night he fell asleep with the 1-year-old on a sofa while Aidan slept on a bed, Mauldin said. Autopsy records and other documents show that the baby sitter put Aidan to sleep about one hour before he was found not breathing.

Hawkins could not be reached for comment.

He worked as assistant principal at East Lincoln High School from 1993 to 1997 and taught at Lincolnton Middle School for nine more years, Lincoln County Schools Superintendent David Martin said.

Hawkins spent his final year in the district working as a janitor, Martin said, but declined to say why.

Aidan's mother, Ashley Stewart, 24, said she believed Hawkins would be a suitable baby sitter. She had known him since high school, and said he often did baby-sitting for her sister-in-law.

Ashley Stewart said she does not believe Hawkins intentionally harmed Aidan.

However, she said, she doesn't believe her son died of natural causes.

Relatives speculate Aidan may have suffocated because his baby sitter put him to sleep on his side in an adult bed. He was found face down, but he had never rolled over before, they said.

"We will never know what happened," said Debbie George, the baby's great aunt.

Tension after the death

A few days after Aidan's death, his family called police to check on the investigation. George said they wondered whether police were doing enough to find out what happened.

Sheriff Tim Daugherty, Mauldin and other officials agreed to meet with the family, but the session grew contentious.

One deputy "kept saying it was SIDS," George said. "I said, 'How do you know it wasn't suffocation?'"

Daugherty told them his department did not have the manpower to send deputies each time ambulances are dispatched, the family said.

Ashley Stewart said she has asked the sheriff's office for copies of police reports, but the department has refused. The department released to the Observer only the initial incident report, and has declined to release subsequent reports.

Aidan's relatives said they are especially upset the sheriff's office waited several days before sending a detective to investigate.

Keller, the sergeant, said a detective visited the home less than 24 hours after Aidan died to collect bedsheets, take pictures and speak with the baby sitter.

Mauldin acknowledged that he apologized to the baby's family for not going immediately to the death scene. However, he said he only did so to mediate differences between the family and the sheriff's office.

"I was trying to be a humanitarian," Mauldin said.

Sheriff Daugherty declined comment, saying he no longer talks to the media. Daugherty became embroiled in controversy previously when he was accused of interfering in a February 2007 drunken-driving investigation. Earlier this year, two felony counts of obstruction of justice and a misdemeanor charge of making a false report to an officer against him were dismissed. In a May primary, he lost the Democratic nomination for a second term as sheriff.

Aidan's relatives are still grieving. They said they believe finding out why he died would help bring closure.

"At times, I think about my son," Ashley Stewart said. "I wish it was me who died instead."

She is now pregnant with her and her husband's second son.

"I am scared with this child something is going to happen," she said. "This child will not be left out of my sight for very long." Staff Writer Franco Ordoñez contributed.