FOUR AND a half years after 15-month-old Prince McLeod Rams was found unresponsive, cold and without a pulse by paramedics responding to a 911 call, his father was found guilty of his capital murder. Judge Randy I. Bellows, hearing the case without a jury in Prince William County Circuit Court, explained his decision April 13 in a 62-page opinion that methodically sorted through the evidence and definitively answered questions surrounding the case. No, the judge concluded, the boy did not die from a febrile seizure or any natural cause, but was drowned or suffocated by his father — who stood to benefit from more than $500,000 in life insurance.

But the conviction of Joaquin S. Rams, set to be sentenced June 22 to life in prison, doesn’t tie up all loose ends. Two other deaths — the murder of Mr. Rams’s ex-girlfriend and the ostensible suicide of his mother — need to be accounted for. There are questions about whether Prince’s death could have been averted had Maryland and Virginia officials been more diligent. Most critical is whether lessons were learned from this tragedy that will help protect other children.

Prince William County Commonwealth’s Attorney Paul B. Ebert can take justified satisfaction from his office’s successful prosecution of a complicated case. But authorities in Prince William need to do some soul-searching about missed signals and missteps in investigations involving Mr. Rams that preceded Prince’s death. Was sufficient attention paid to the 2003 murder of ex-girlfriend Shawn Katrina Mason? Why did police brush aside suspicions when his mother died and he benefited from her insurance? Then there was the botched inquiry into allegations surrounding a disputed sexual encounter involving Mr. Rams and the teenage sister of Prince’s mother, Hera McLeod.

Ms. McLeod, as she wrote recently in a Post essay, faults the family court system that made her son vulnerable to harm. She had sole legal and primary physical custody of her son and fought fiercely to prevent Mr. Rams from having unsupervised visits. But a Montgomery County Circuit judge allowed them, and Prince died on the fourth one. “Parents,” Ms. McLeod wrote, “should not have to prove beyond a reasonable doubt that the other parent is dangerous.”

Part of the problem, according to lawyers experienced in custody cases, is an inherent bias, even distrust, of parents — in most cases women — who without physical evidence raise safety as a reason to limit or prevent contact with the other parent. “I hate it when I have to tell a client who genuinely fears for her child that she risks appearing as an alarmist and alienating the court,” one attorney told us. “I hate it even more when I have to tell her she has no choice but to abide by the court’s order.”

No judge can lightly suspend parental contact with a child. But the interests of children always should take precedence. Montgomery County, reacting in part to this case, appears headed toward opening its first monitored child exchange and supervised visitation center, which would give judges a better option in cases such as this. It’s long overdue. When it opens, it would be fitting for it to bear Prince’s name.