It took 5 1/2 years to bring Mark M. Fisher to trial in the death of an elderly Washington County woman who was terrorized by robbers posing as gas company workers.

It took jurors just 55 minutes to convict him of 11 crimes, including second-degree murder.

The verdict means Mr. Fisher, 24, will spend the rest of his life in prison.

He said nothing as sheriff's deputies led him out of the Washington County Courthouse and back to his jail cell. Mr. Fisher walked right by relatives of his victim, 89-year-old Freda Dale, but they ignored him and focused instead on the verdict.

"I am elated," said Betty Hamilton, of Gastonia, N.C., one of Mrs. Dale's daughters.

She said the conviction gives her peace of mind, even though Mr. Fisher's three cohorts in the crime remain unidentified.

"They'll be caught in time. With all the improvements in DNA technology, the cold-case detectives will get them eventually," Ms. Hamilton said.

An old science and a new one, fingerprints and DNA, led to Mr. Fisher's conviction.

State police said they found his DNA on a cigarette butt outside the home in Peters that Mrs. Dale shared with her 90-year-old husband, Shannon.

Inside the Dale's house was a fingerprint on an envelope that matched Mr. Fisher's right thumb, police said. Experts also testified that DNA on duct tape the robbers used to tie up Mrs. Dale could have come from Mr. Fisher.

Terrified by the intruders, Mrs. Dale died of a heart attack after they beat her husband. He survived the attack but died this year at 95.

Even at his advanced age, Shannon Dale still wanted to go to court to see his wife's attackers put on trial, said Don Hamilton, a son of Mrs. Dale's from her first marriage.

Mr. Fisher's parents, both from Texarkana, Ark., also were in court. They insisted their son was a victim of circumstance, not a killer.

The father, Rusty Fisher, said in an interview that Mark Fisher did paving work on the Dales' driveway before the murder, accounting for his DNA and fingerprints at the home.

But public defender Glenn Alterio produced no witness who could establish that Mark Fisher worked for the Dales. Instead, Mr. Alterio called Mr. Fisher's mother and sister-in-law. They testified that Mark Fisher was in Arkansas with them on Jan. 29, 2003, the day robbers attacked the Dales.

His mother, Vicki Fisher, said she was certain of the date because she had a horrible argument with her son that day. She said the Texarkana Gazette reported that very morning that Mark Fisher's girlfriend had been arrested as part of a ring running a methamphetamine lab. Her daughter-in-law, Karyl Fisher, said she witnessed part of this argument.

During cross-examination, prosecutors got both of them to admit they had never mentioned his alibi until two weeks ago. Karyl Fisher also admitted lying to authorities in the past. She pleaded guilty to obstructing police when they tried to arrest her husband on warrants.

None of the seven men and five women on the jury looked at Mr. Fisher as they walked into the courtroom with their verdict. But two of the men stared at Mr. Fisher as their foreman read the series of guilty verdicts. In addition to murder, jurors convicted him of robbery, burglary, aggravated assault and being part of a conspiracy with the unidentified assailants.

President Judge Debbie O'Dell Seneca said she would wait to sentence Mr. Fisher until she receives a report on his background and criminal history. But Judge O'Dell knows that Mr. Fisher already is serving a 70-year prison sentence in Arkansas.

His most notorious case was similar to the crimes against the Dales. Mr. Fisher and an accomplice barged into the home of an 88-year-old man, threw him to the floor and stole the $1,060 he was carrying.