ANNAPOLIS, Md. — Kirk Noble Bloodsworth, a beefy, crew-cut man whose blue T-shirt read “Witness to Innocence,” took the microphone in a church hall here and ran through his story of injustice and redemption one more time. Twenty years ago, he walked out of a Maryland prison, the first inmate in the nation to be sentenced to death and then exonerated by DNA.

About 60 activists against the death penalty listened with rapt attention, preparing to descend on state legislators to press their case. Maryland appears likely in the next few weeks to join the growing list of states that have abolished capital punishment. Some longtime death penalty opponents say no one in the country has done more to advance that cause than Mr. Bloodsworth. But ending executions in Maryland, the state that once was determined to kill him, would be a personal victory for him.

Even for proponents of capital punishment, Mr. Bloodsworth’s tale is deeply unsettling. In 1984, he was a former Marine with no criminal record who had followed his father’s profession as a waterman on the Eastern Shore of Maryland. A woman glimpsed on television a police sketch of the suspect in the rape and murder of a 9-year-old girl outside Baltimore. She thought it looked like her neighbor Kirk, and she called the police.

From there, with the police and prosecutors under intense pressure to solve the crime, it was a short route to trial, conviction and a death sentence for a man whose Dickensian name, after all, seemed to imply guilt.