The testimony of an expert pediatric forensic pathologist apparently sealed the murder conviction of Candace Croff Cartagena in the asphyxiation of her 8-year-old daughter more than three years ago in their East Amherst home.

Both Erie County Judge Thomas P. Franczyk and prosecutors cited the testimony of Dr. Kim A. Collins in countering the defense contention that Bianca Cartagena died a natural death due to an enlarged heart.

The judge convicted Cartagena following a nonjury trial.

Ruben Cartagena, the defendant’s former husband, did not attend the trial because it was “too painful” but was present for the verdict.

“A little bit of closure,” he said after the judge announced the verdict. “Like I said, nothing is going to bring back my daughter, but at least we know the killer is going to be in jail and off the streets.”

He said he was convinced that Cartagena was guilty, and he pushed – with the help of the Amherst Police Department – for Cartagena’s indictment for 2½ years.

“She was the only one in the house, and my daughter was dead,” he said. “It was kind of a no-brainer that she had done it, with her anger and the way that she was.”

He hopes his ex-wife receives the maximum penalty.

“I would like to see her away for a long time so she doesn’t do this to anybody else,” he said.

He said his divorce from Candace Cartagena, which was in the works when Bianca was killed, has been official for about two years.

“She changed through the years dramatically into who you see now: a murderer,” he said.

He said he hopes people remember Bianca as “a fun-loving person who just loved life, loved doing everything, and probably to this day still loves her mother even though she killed her.”

Franczyk said the defense’s expert witness, Dr. Jonathan L. Arden, saw clear evidence that Bianca died naturally as a result of dilated cardiomyopathy. But Collins found she had an essentially normal heart that showed no signs of the heart disease.

“Neither Dr. Collins nor Dr. Vertes perceive Bianca’s heart size and weight to be significantly abnormal,” Franczyk said, referring to Dr. Dianne R. Vertes, the then-Erie County medical examiner who performed the autopsy.

“But Dr. Arden saw these as significant factors.”

The judge said the question was whether Bianca’s heart was so structurally and mechanically compromised as to cause her death suddenly without warning.

“In this court’s view, while Bianca’s heart may have been somewhat larger and heavier than normal, there is just no basis on this record to comfortably conclude that an otherwise healthy, active and asymptomatic 8-year-old child (whose heart looked normal on an X-ray 14 months earlier) would just keel over and die from DCM (dilated cardiomyopathy),” he said.

“Such a conclusion is not supported by the scientific literature on the subject introduced into evidence and is contrary to common sense.”

The judge cited several factors in concluding that Bianca’s death was due “not to DCM, but to a deprivation of oxygen, which was not accidental in origin.”

He noted the bursting of tiny blood vessels in her eye and eyelids, significant congestion of the thyroid, facial pallor indicating pressure had been applied around her nose and mouth, and evidence of a struggle in the bed where she was found, including her messed, matted hair, the awkward position of her body with her shirt pulled up, one sock half off and the other on the floor, the partially removed sheets and the disheveled pillows.

“Based on the evidence, this court rejects the conclusion that Bianca Cartagena … just happened to die a natural death from a diseased heart on the very same day that her deeply troubled mother, in whose sole company she found herself, chose to take her own life,” Franczyk said.

“Such a circumstance would stretch the concept of coincidence to a new absurdity.”

The judge added that while it was not clear whether asphyxiation occurred by compression of the neck or abdomen and/or smothering, “what is clear to this court beyond a reasonable doubt is that Bianca Cartagena died from asphyxiation at the hands of her own mother.”

“Moreover, inasmuch as death by asphyxiation requires sustained pressure and blockage of the airways in the face of likely resistance, the only reasonable conclusion in this case is that her death was brought about intentionally,” he said.

“Therefore, this court finds the defendant guilty as charged of murder in the second degree.”

The judge also cited Cartagena’s failure to call 911 when she found Bianca dead next to her in her bed after the defendant said she took numerous pills in an attempt to kill herself because of marital and financial problems.

Cartagena, 35, will be sentenced at 2 p.m. Aug. 26. She faces a minimum prison sentence of 15 years to life for the conviction, which could carry a maximum term of 25 years to life.

Cartagena showed no reaction when the verdict was announced.

Defense attorney Joseph J. Terranova said he will appeal the verdict after Cartagena’s sentencing. “She’s pretty distraught because we felt that with three medical examiners saying three essentially different things, that that created reasonable doubt,” Terranova said.

“And, of course, cause of death and manner of death are the foundation of this type of case, so we thought that we had a good reason for acquittal, and the judge didn’t agree, and that’s the way it works.”

The defendant’s mother, stepfather and sister left the packed courtroom after the verdict without commenting.

Candace Cartagena was indicted in May 2013. During the 2½ years between Bianca’s death and her mother’s indictment, family members called for her arrest and publicly criticized District Attorney Frank A. Sedita III for not moving more quickly to bring the case to a grand jury.

Sedita said Monday that it took so long to indict Cartagena because prosecutors had only circumstantial evidence that she had killed her daughter. He said they anticipated that the defense would contend that Bianca died from a heart condition and realized that they would need scientific evidence from experts to disprove that contention and to prove instead that she died of intentional asphyxiation.

Eventually, they persuaded Collins, one of the leading pediatric forensic pathologists in the nation, to examine the medical evidence and testify.

Assistant District Attorney Thomas M. Finnerty, who prosecuted the case with Assistant District Attorneys Kristin A. St. Mary and Ashley M. Morgan, cited Collins’ testimony that if Bianca died of dilated cardiomyopathy, it would be the first time that an otherwise healthy, active 8-year-old died from the heart disease.

Sedita said the forensic evidence sealed the case.

“We went out and found the best forensic pathologist in the country,” he said, referring to Collins, forensic pathologist at the Fulton County Medical Examiner’s Office, Emory University School of Medicine, in Atlanta.

The district attorney said Collins’ testimony came at a high price. He couldn’t cite a figure but said it was enough to pay for her child’s college education for a number of years.

St. Mary said Bianca suffered a long death that required a sustained effort by her mother, who she said “had plenty of opportunity to stop but didn’t.”

Finnerty said Collins called the death torture.

Candace Cartagena was accused of suffocating her daughter during a Nov. 29, 2010, visit at her home on Greengage Circle, where she lived alone after Ruben Cartagena moved out and Bianca went to live with her maternal grandparents in North Tonawanda because she could not take care of her.

After she failed to return the girl to the grandparents’ home the next day, Bianca’s grandfather and the defendant’s sister found Bianca’s body in her mother’s bed and called police.

After examining the bedroom, police found Cartagena in a backyard shed, where, according to prosecutors, she pretended to be semiconscious at first but then awoke and answered their questions.

Cartagena contended that she had tried to kill herself because she was distraught over her ongoing divorce, prosecutors said.

When police asked her if anything had happened to Bianca, she said she didn’t know because she had taken the pills. When police told her that Bianca was dead, Cartagena did not respond, prosecutors said.

News Staff Reporter Aaron Mansfield contributed to this report. email: