A District law that prohibits the filing of murder charges against an assailant if the victim dies more than a year and a day after an injury was struck down yesterday by a unanimous panel of the D.C. Court of Appeals.

The three-judge panel said the law, which grew out of concerns about the precision of medical science in the 18th century, was an anachronism and called it "capricious and senselessly indulgent" and "unreasonably generous toward assailants who kill."

The panel, however, recognized that there may be value to having some kind of a temporal definition of death for homicide prosecutions, and suggested that the D.C. Council or Congress consider the issue.

The ruling joins the District with several state courts and legislatures across the country that have abolished the so-called year-and-a-day rule or extended the time limitation. Only about 20 states, including Maryland, still have the traditional year-and-a-day rule in effect.

In the case before the appellate panel, prosecutors attempted to charge Ricky L. Jackson with second-degree murder after a man died 14 months after being shot by Jackson. Jackson already had been convicted by a jury of assault with a dangerous weapon in the incident when the man died from a gunshot wound to the head after spending months in a coma.

In her 31-page opinion for the panel, Judge Judith W. Rogers said the case highlighted the "absurdity of continued application of the rule."

"Surely, the dictates of justice and public policy favor removal of a 'capricious' obstacle to a prosecution for murder where the victim died 14 months after having his brains blown out by a gunshot to the rear of his head which rendered him a paraplegic," wrote Rogers, who was joined by Judges Frank Q. Nebeker and Julia Cooper Mack.

However, the panel upheld a lower court ruling by D.C. Superior Court Judge Geoffrey M. Alprin dismissing the second-degree murder indictment against Jackson because they said it was "fundamentally unfair" to apply their ruling retrospectively "where a prosecution for murder was barred nearly five years ago."

Principal Assistant U.S. Attorney Timothy J. Reardon III, whose office is charged with enforcing the law, praised the ruling but said, "We regret, however, that we cannot prosecute Mr. Jackson." Jackson is serving a sentence of 43 1/3 months to 11 years at a federal penitentiary in Connecticut on assault and other charges stemming from the same incident. If convicted of second-degree murder Jackson could have been sentenced to up to life in prison.

"We are very pleased the court has abandoned an archaic rule," said Reardon.

The law, which is rooted in English common law, grew out of a belief that medicine was an imprecise science that precluded the determination of an exact cause of death, and, as a result, jurors should be prevented from being "unduly speculative" about assessing the relationship between an assault and death, particularly as a significant period of time elapsed before death.

In her opinion, Rogers noted that recent advances in medical technology had reached a point where a modern juror is no longer faced with the "same causation problems as was his medieval counterpart" and that, additionally, defendants are still protected in cases where there is uncertainty about the cause of death because the government still had the burden of proof.

"Surely the windfall for the assailant is a high price for society to pay," wrote the judge.