MONTGOMERY COUNTY has put both attention and resources into the fight against domestic violence. A special unit in the State’s Attorney’s Office is charged with handling these difficult cases, and the county’s well-regarded Family Justice Center consolidates under one roof public and private agencies serving families affected by domestic violence. That there have been such strides makes all the more troubling the breakdowns that led to the death of Heather McGuire.

Ms. McGuire, 36, was killed this month, apparently by her estranged husband, who — in­cred­ibly — had been released just the day before for twice violating a protective order not to go near her. Philip Gilberti shot his wife in a van as the two were headed down Connecticut Avenue the next morning, police say. He then pushed her body onto the road and later killed himself.

It is clear, from court records and people who dealt with the couple, that the two had a difficult history complicated by their individual troubles. Such cases defy easy solutions, and it’s hard to say what might have been. But the facts of this case — a man with a history of violence (including a charge of attempted murder) is released without bond after twice being taken into custody for allegedly threatening his estranged wife — demand thorough review by county officials. Was the failure something as simple — but no less unacceptable — as the judge not having all the information because the court computer was down? Or does the problem go to deeper failures in the system? Advocates for victims of domestic violence, while crediting the county for progress in recent years in reducing the number of fatalities, say more could be done to make protective orders a more effective means of safeguarding women. They worry about a mind-set in which the really tough cases are seen as unsolvable.

One only has to recall Ms. McGuire’s chilling prediction to the court — “My children believe he is gonna kill me” — to know that something went wrong here. A review of how this case was handled, which is routine in all fatalities resulting from domestic violence, is underway. It’s too late to help Ms. McGuire but it’s important that steps be taken to prevent more tragedies.