The doctor who performed the autopsy on Hillary Tyler's infant son ruled the baby had drowned as a result of a homicide.
Associate State Medical Examiner Jonathan Thompson told jurors in Tyler's first-degree murder trial Wednesday in Fort Dodge he came to that conclusion after examining the baby boy's body and listening to law enforcement interviews with Tyler.
Thompson's determination came in part because of Tyler's videotaped interview with Iowa Division of Criminal Investigation Special Agent Mike Roehrkasse, who spoke with her on Sept. 20, 2011, the day after Tyler allegedly killed the newborn in a Fort Dodge Super 8 motel room.
In the interview, which was shown to the jury, Tyler initially said the baby didn't move or cry after she gave birth to it while standing up in the bathroom.
But after Roehrkasse asked Tyler if she went to the motel with any intention of not keeping the baby, she burst into tears and said the baby did cry after she gave birth.
"I left the baby in the bathtub and turned on the water," she told the agent, adding that she left the baby in the tub face down and didn't know the temperature of the water.
She let the water get to about 2 to 3 inches high before leaving the bathroom, she said.
"I really appreciate you being honest," Roehrkasse told her. "I really do."
Tyler said she knew she was pregnant, but didn't tell anybody about it - including the baby's father, Rodney Cyphers, who she lived with.
"I didn't know what to do," she said. "I didn't know what Rodney's reaction would be if I told him. I know that sounds stupid."
She believed that Cyphers didn't want children, she said.
"I'm sure he would have been fine with it," Tyler told Roehrkasse. "I was just scared."
Toward the end of the interview, DCI Special Agent in Charge Larry Hedlund asked Tyler if she would repeat what she'd done again.
"No, I wouldn't do it again," she said. "It was a terrible thing what I did."
Tyler was taken to Trinity Regional Medical Center after the interview, where she was treated for low hemoglobin count and birth-related injuries.
Hedlund and Roehrkasse asked Tyler several followup questions on Sept. 21, the day after her arrest.
Jurors heard the entire interview, which was an audio recording.
Tyler told Hedlund she considering going to a hospital, but didn't realize there was one in Fort Dodge.
"I thought about calling Rodney or calling my mom," she said. "I was just scared."
She also said she was most worried about Cyphers' reaction.
"I wasn't sure if Rodney wanted a baby," Tyler said. "I just wanted him to be happy."
Hedlund asked Tyler if she had any regrets.
"Of course, yeah," she said. "If I had to do it again I would tell Rodney I was pregnant and have a normal pregnancy."
He also asked Tyler if there was anyone she wanted the DCI to contact.
"Rodney," she said through tears. "Tell him that I'm sorry."
Thompson testified Wednesday about the physical examination portion of the baby's autopsy.
"I discovered fluid within the trachea, which was in part amniotic fluid," he said. "Part of that fluid was also water."
However, Thompson said, there's no way to tell if that water was part of the amniotic fluid or came from breathing in water.
"There's no way to separate out the fluid and bath water," he told jurors.
He also said there was evidence that parts of the baby's lungs had expanded, while others were collapsed.
"Given the history that Baby Tyler had cried and moved, that suggests that he took a breath," Thompson said.
One of Tyler's attorneys, Joseph McCarville, asked Thompson under cross-examination whether he could rule out any other illnesses or conditions.
"Is it true that there's nothing inconsistent with the case that the child may have lived momentarily then died after childbirth?" McCarville asked.
"It's certainly possible the child could have been deceased before being placed in the tub," Thompson said.
He also told McCarville that without information provided by law enforcement, the baby's cause and manner of death couldn't be determined.
However, when questioned by Assistant Iowa Attorney General Laura Roan, Thompson stressed the importance of investigative work.
"It's vital in determining the manner and cause of death," he said. "I have to ask other people what's missing. The history is absolutely essential."
In the morning, jurors heard testimony from Dr. Dan Cole, Webster County medical examiner, who was responsible for making sure the body was transported to the state medical examiner's office in Ankeny.
During his testimony, photos of the baby's body were shown to the jury. Cole said a portion of the umbilical cord, gathered from the motel room, and the placenta, which was found at the trailer where Tyler and Cyphers lived in Coalville, were also placed in the cooler, which was then sealed shut with evidence tape and driven to Ankeny.
Cole was also the doctor who examined Tyler in the emergency room at Trinity Regional Medical Center.
"When she was brought in, I saw her and examined her," Cole said. "We gave her a physical screening, and then I left her in the care of a local obstetrician."
Cole said Tyler suffered from pre-eclampsia, a condition that can affect pregnant women.
"She would have become hypersensitive, suffered from headaches and swelling," Cole said. "Those who suffer from pre-eclampsia are 'cured' by delivery."
He also testified Tyler was alert and aware of her surroundings when he examined her.
The prosecution rested its case shortly after 4 p.m.
Judge Thomas Bice said the defense will begin its case at 9 a.m. Friday because its expert witness will not be available until then.
"My hope is that we will get the case to you on Friday," Bice told the jury.
The case is also being prosecuted by Webster County Attorney Ricki Osborn. Charles Kenville is also serving as Tyler's defense counsel.