When Hera McLeod found out she was pregnant in the fall of 2010, she moved in with her fiance, Joaquin S. Rams. But their relationship grew colder not warmer, McLeod said. She said Rams told her he wouldn’t help with child care, that she paid the mortgage and all the bills because he was supposedly broke, and that after their baby was born, he refused to even hang out with his new son.

About two weeks after the birth of Prince McLeod Rams in July 2011, Joaquin Rams slept with his fiancée’s sister, so McLeod took Prince and moved out. McLeod said the only contact she had with Rams in subsequent months was an e-mail from his lawyer, asking her to return his car. “He didn’t mention anything about Prince,” McLeod said.

A custody battle over the boy ensued. McLeod was granted custody, and Rams was granted regular visitations. On one of those visits, Prince collapsed in Rams’s Manassas, Va., home and later died at age 15 months. Two weeks later, McLeod found out that her ex-fiancé had taken out more than $500,000 in life insurance on their son.

After McLeod testified in a tense courtroom late Wednesday, the prosecution in Prince William County, Va., rested in the capital murder trial of Rams. Rams, who sat with his head down through much of his ex-fiancée’s testimony, did not testify, and his lawyers have not explained why he took out three policies on the newborn boy in the fall of 2011.

But Rams has also claimed he is innocent. And prosecutors seemed to acknowledge Wednesday that they are backing away from their long held theory that Rams drowned his son, after a spate of defense experts challenged the autopsy findings of the original medical examiner in the case. The uncertainty caused Circuit Court Judge Randy I. Bellows, who is deciding the case without a jury, to begin exploring the possibility with witnesses that Prince was suffocated, and defense lawyer Chris Leibig argued that “There is no reasonable trier of fact who can say what the cause of death was.”

Chief Deputy Commonwealth’s Attorney James Willett responded, “The Commonwealth does not have to prove a cause of death.” He said the case could be likened to murder cases tried without a body ever being found, and said, “We are not bound by a particular theory…We have established it was a hypoxic event associated with drowning and/or suffocation.”

That sets up an interesting closing argument for Willett on Thursday, who opened the case by saying evidence would show Prince had drowned. “Anything I say in opening is of no evidentiary value,” Willett said. And then, after the defense argues, it will fall to Bellows to analyze the 11 days of testimony, about 1,000 pages of exhibits, and issue a verdict, which he said he will do next Thursday. If he convicts Rams of capital murder, the sentence is a mandatory life term in prison. Prosecutors withdrew the death penalty, which can be imposed in Virginia for the killing of a child, shortly before the trial began.

Also Wednesday, three prosecution experts in pediatric neurology testified as rebuttal witnesses that Prince could not have died from febrile, or fever-induced, seizures. Prince had seven febrile seizures in the months before his death, court records show, and the defense has suggested that a seizure may have led to the cardiac arrest which overtook the toddler on Oct. 20, 2012. Rams told authorities that he saw Prince seizing, rushed in and scooped him up, felt that he was really hot and called for a housemate to dial 911 while he splashed cold water on the boy to cool him down. When paramedics arrived, they found Prince cold, wet and not breathing, and his heartbeat was not restored for 40 minutes. He was kept on life support, but died the next day.

Bellows, as the fact-finder in the case rather than just the referee, again took an active role on Wednesday in questioning a witness, examining both comments made on the 911 tape and statements Rams made to paramedics that day. No one has testified to any statements Rams has made about the incident — and no police detectives from Manassas City testified at all in the trial — but reports written by paramedics about their interactions with Rams were entered into evidence en masse on the first day, and Bellows cited them in his questions to noted child seizure expert Shlomo Shinnar of New York City.

Rams told paramedics that he saw Prince seizing, “he was very hot so I put him in the bathtub like I was told,” Bellows said the reports stated. The judge asked Shinnar, “Is it your understanding based on that, that the father is reporting witnessing an active seizure in progress?” Shinnar replied, “That scenario does not make sense medically.” He said if someone is in cardiac arrest, “You can have a seizure, but it’s going to be very brief.”

Bellows said Rams could be overheard telling paramedics on the 911 tape “that he observed the child taking long breaths, and then he just couldn’t breathe. Is that consistent with being in cardiac arrest?” Shinnar again said, “No. If you go into cardiac arrest, you’re going to stop breathing in seconds.”

Bellows did reverse himself Wednesday on his earlier interpretation of the beginning of the 911 tape, where he said he heard Rams say, “He’s shaking and he stopped breathing.” Bellows then asked a defense witness last week if it were possible to be shaking and in cardiac arrest, to which the witness said no. The next day, defense lawyers said Bellows had heard it wrong, that Rams said his son “was shaking,” not that he was currently shaking. Bellows said he relistened to the tape with headphones and “I am convinced, he said he ‘was,’ not ‘he’s.'”

Shinnar also weighed in on Prince’s plummeting temperature, from feeling hot when Rams held him to cold when paramedics arrived. “It is extremely improbable that you could be cold a few minutes later,” Shinnar said. And he was emphatic that “a febrile seizure itself has never been found to be a cause of death.” Pediatric neurologists Robin Foster of the University of Richmond and Sylvia Edelstein of Bethesda, Md., who examined Prince a month before he died, also ruled out febrile seizures. But none are pathologists, and so could not say how Prince died.

McLeod said Prince was a happy boy, living with his mother and grandparents in Gaithersburg, Md., who enjoyed swim classes and was developing normally, though he frequently had fevers and upper respiratory infections. McLeod and her father also had febrile seizures as children, so she and her doctors were not overly concerned when Prince started having them.

McLeod said Prince didn’t have a seizure until he went on an unsupervised visitation with Rams in September 2012. But Leibig showed her records of a June 2012 doctor visit reporting that Prince’s grandmother glimpsed him having the same type of seizure McLeod had as a child, and an assessment that Prince had “febrile convulsions.” McLeod said, “This is the first time I’m looking at this.”

Leibig asked if Prince had been prescribed Diastat, a drug used to combat seizures as they are happening. McLeod said yes, but she “made the decision it wasn’t appropriate” and didn’t fill the prescription, and did not mention it to Rams.

McLeod acknowledged she kept a blog, “Cappuccino Queen,” to document her travails with Rams and her experiences raising Prince. (Rams launched a counter-blog, “King Latte,” before he was arrested in January 2013.) But when Leibig showed her entries from the blog about Prince’s seizures, McLeod said, “I can’t verify the authenticity of this. It was several years ago.” She said she could not recall dates of seizures or Prince’s reported temperatures. A blog post on Oct. 20, 2012, noted her hesitance at dropping off her “feverish, scared baby” for a visitation with Rams, but McLeod said she couldn’t remember writing that.

McLeod said she believed Rams did not work and had no money while they lived together. Leibig asked her about bank records showing Rams had $26,000 in his account in June 2011, and $270,000 in deposits in 2010. “That’s news to me,” McLeod said.

When McLeod was done, and the prosecution rested, Leibig asked Bellows to strike the case. He said the case changed when Willett asked a defense expert if it were possible for a large man to suffocate a child with a pillow, without leaving any marks. “The evidence has substantially changed,” Leibig argued. “Drowning can’t have happened…Which is why Mr. Willett began the line of questioning about the pillow. That that would then become the cause of the death in this case would be an astonishing legal switchup. The commonwealth hasn’t established a cause of death.”

Willett responded that he didn’t have to prove a cause of death, and Bellows denied the motion without comment. Closing arguments start at 10 a.m. in the Prince William courthouse.