April 29, 2024
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Mason Shannon retrial: Asphyxia or bad heart? Experts dispute Castelli death

Shannon tells judge he’ll take the stand Friday

By Tom Collins
Mason Shannon appears during a bench trial at the La Salle County Governmental Complex in Ottawa. Mason Shannon, 48, of Newton, Iowa was convicted of involuntary manslaughter for placing Michael Castelli, of Ottawa, into a lethal chokehold during a struggle outside the Bonnie Plants growing facility in 2017.

Shannon, 49, of Newton, Iowa is standing for a do-over trial this week on whether he acted in self defense or acted recklessly when he placed Michael Castelli into a headlock during a struggle at the Bonnie Plants facility. (Scott Anderson)

The judge trying Mason Shannon for involuntary manslaughter has a decision to make: Did victim Michael Castelli die from asphyxia or a pre-existing heart condition?

Two experts who testified Thursday in La Salle County Circuit Court offered very different opinions on how Castelli died in July 2017 in rural Ottawa.

[ Mason Shannon retrial Day 1: 'It was chaotic – a lot happening very quickly’ ]

[ Mason Shannon retrial Day 2: Attorneys disagree: Was Castelli alive after headlock? ]

Shannon, 49, of Newton, Iowa is standing for a do-over trial this week on whether he acted in self defense or acted recklessly when he placed Castelli into a headlock during a struggle at the Bonnie Plants facility. Castelli could not be revived. Shannon could face up to five years in prison if Judge William Dickenson rules he killed Castelli recklessly or without lawful justification.

Dr. Valerie Arangelovich, a board certified forensic pathologist, testified Thursday on behalf of prosecutors, who allege Shannon overdid it when he restrained Castelli.

Arangelovich said she conducted an autopsy and spotted a series of small blood vessels that had burst and that indicated death from asphyxia. She also found some hemorrhages in Castelli’s neck that were consistent with a chokehold.

Arangelovich testified a chokehold can induce death in three to six minutes. A witness who testified earlier at trial, Jordan Wilkinson, estimated 10 minutes elapsed between when Shannon placed Castelli into the hold and when he released him.

And while Arangelovich did observe Castelli’s heart was enlarged – not uncommon among athletes and active persons – “I do not see any reason why his heart would contribute to his cause of death.”

But Shannon’s lawyers argued that Arangelovich rendered her opinion too soon – key witness statements were made available after the autopsy was completed – and they then produced a contrary opinion as to cause of death.

Dr. James Filkins, also a forensic pathologist, reviewed Arangelovich’s report as well as witness statements not available to her. Filkins disagreed with her conclusions.

Filkins testified the burst blood vessels could have resulted from CPR, not necessarily from asphyxia, and the neck injuries could have resulted from the struggle. He disagreed with Arangelovich’s belief that a chokehold induced asphyxia because the hold, from the statements and evidence he saw, wasn’t sustained long enough to induce death.

Filkins also testified Castelli’s heart was abnormally enlarged and the wall thickness in one of the chambers was abnormally thickened.

“If the heart is enlarged to this degree,” Filkins said, “that enlargement can set the person up for sudden cardiac death.”

Factor in the alcohol and drugs Castelli had ingested plus the stress of a prolonged fight, Filkins said, “then I think it’s very likely he was going to have a fatal cardiac event.”

Prosecutors were openly skeptical of that assessment. Castelli was 32 years old and physically fit – he bicycled and played basketball regularly – which put him less at risk of a fatal cardiac event than other age-health brackets.

The trial resumes at 1:30 p.m. Friday. Shannon told the judge he intends to testify. Dickenson previously said he intends to take the case under advisement, which means no verdict this week.