A Manassas man who authorities said took out more than $500,000 in life insurance policies on his 16-month-old son was charged with first-degree murder Friday in the alleged drowning of the boy in October.

The child, Prince McLeod Rams, had been the subject of a custody dispute. Over repeated objections from the boy’s mother, a family court judge in Montgomery County allowed the father, Joaquin S. Rams, now 40, to have unsupervised visits with Prince in his Prince William County home.

Prince’s mother, Hera McLeod, said in an interview Friday that she and Rams, who were not married, were together as a couple for about 18 months, until she ended their relationship in July 2011, a few weeks after Prince’s birth.

McLeod said she was told by investigators that in the months after she and Rams broke up, Rams bought three insurance policies on Prince’s life, listing himself as the only beneficiary. The death benefits, which have not been paid, were $443,000, $50,000 and $35,000, McLeod said, relating what investigators told her.

During one of Rams’s unsupervised visits with Prince, on Oct. 20, the boy suffered what a Prince William Hospital report called “obvious and unexplainable injuries,” including bruises above his left eye and blood in his nose. Prince, who died the next day, had arrived at the hospital naked and wet, the report said.

The report also said Prince had a history of seizures.

Although authorities have not commented extensively on the probe of Prince’s death, a law enforcement official in Prince William who is familiar with the case confirmed that the death benefits of the insurance policies totaled more than $500,000.

McLeod, 32, shared other details that she said were related to her by investigators.

According to what she heard from detectives, McLeod said, Rams told investigators that Prince suffered a seizure during the Oct. 20 visit and that he tried to help the boy by placing him in a bathtub filled with cold water and by splashing water on the child’s face.

But McLeod said she was told that an autopsy found that Prince’s lungs and other organs were saturated with water. “There was so much water in his system, it couldn’t possibly have come from just a little bit being sprinkled in his face,” she said.

On Friday, three months into the investigation, authorities in Prince William arrested Rams. “He’s charged with premeditated murder,” Commonwealth's Attorney Paul B. Ebert said. Rams has denied any wrongdoing in postings to a blog that he maintains, in which he criticizes people who suspect him of causing his son’s death.

Ebert said that under Virginia law, based on the circumstances of the alleged crime, the charge against Rams eventually could be increased to capital murder, meaning he could be sentenced to death if convicted.

It was unclear Friday whether Rams has hired a criminal defense attorney. His attorney in the custody dispute could not be reached.

McLeod said the allegation that Prince was slain did not surprise her. “I have known since the day I saw my son in the hospital,” said McLeod, who was once a contestant on the CBS-TV reality program “The Amazing Race.”

As for Rams’s arrest, she said: “That feels good to know. For this long, I’ve been trying to get people to understand what I already knew.”

Last year, citing concerns for the boy’s safety, McLeod wanted Judge Michael J. Algeo to deny visitation rights to Rams. After court proceedings, Algeo initially allowed only supervised visits, appointing a retired police officer to monitor Rams and Prince when they were together. Eventually, Algeo lifted the supervision requirement.

During the court fight over custody and visitation, a Manassas police detective testified that Rams remained a suspect in the unsolved shooting death of a former girlfriend, Shawn Katrina Mason, in 2003. Rams had an opportunity and motive to commit the crime, the detective testified. A Prince William social worker noted in a report that Rams mistakenly thought he was the beneficiary of Mason’s life insurance policy.

Rams, in his family court testimony, denied any involvement in Mason’s death.

The exact basis for his arrest in Prince’s death remained unclear Friday.

The affidavit that authorities presented to a judge to obtain a search warrant was not immediately disclosed. But it probably will be made public in court next week.

“I am a devoted father, and far from the horrible person I have been made out to be in the media,” Rams said in a Jan. 8 post to his blog. “The memories of [Prince] calling me ‘dada’ will be forever locked in my mind.”

McLeod also has a blog. In a July 12 post, she worried about a boy who was too young to protect himself. “If anything happens to Prince,” McLeod wrote, “he can’t say anything. He’s not old enough to be talking.”