On an October night 36 years ago, a man raped a woman near her apartment on Congressional Lane in Rockville.

After a few years, the investigation languished. But two years ago, Montgomery County Police reopened the case — one of its oldest cold cases — and used DNA evidence, which had been collected decades earlier, to tie Richard Ricketts to the crime.

On Thursday, a jury in Montgomery County Circuit Court convicted Ricketts of first-degree rape and two charges of first-degree sexual offenses after DNA from the crime matched his profile. Ricketts, a convicted sex offender, had been living in Florida.

The victim, now in her 60s, whom The Washington Post is not identifying to protect her privacy, had been working at the time of the attack as a sales manager in the gourmet food department at a Bloomingdale’s in White Flint.

In court this week, she described the attack.

Sometimes, she worked late, until the store closed around 9:30 p.m., before she made the 10-minute drive home.

The night she was raped, in October 1977, she drove home and backed into her parking spot, as she always did.

As she was walking toward her apartment, she heard footsteps behind her, she said.

“I glanced back but kept walking,” the victim said. Then, she said, her attacker came up behind her, put her into a chokehold, and dragged her down onto the grass.

He had her by the throat, she said, and told her to shut up and stop screaming.

Then, he raped her. “It was all very quick,” she said.

“I was afraid for my life at that point,” she told the jury.

The victim’s neighbors, who heard her screams, chased the man, but were unable to catch him.

Police interviewed her, took forensic samples and conducted an extensive investigation over the next two years, but they couldn’t close the case, according to testimony at trial.

The victim looked at mug shots of potential suspects but couldn’t recall his face, she testified. She remembered that he was white, of average height and very strong — but nothing more.

The image that stuck in her mind was his “orange red ski-type sweater, in my face.”

Former Montgomery County police officer and detective Paula Obal testified in court about her efforts to help solve the case three decades ago.

Obal, who now coaches softball, was a police officer at a time when the department didn’t have many female officers, she said in court. Because of that, she assisted on investigating hundreds of sex crimes, including this one.

Obal stayed with the victim while doctors examined her and worked to find the man behind the crime.

Ricketts became a suspect when police checked DNA evidence from the crime against a national database and found a match. Ricketts’ DNA was collected in Florida, where he was convicted of burglary and rape in 1999, according to charging documents.

“It’s a complete match,” Julie Ferragut, a forensic expert who tested the original evidence, told the jury. She said the probability of finding another white person with the same genetic coding in the continental U.S. was roughly one in 280 quadrillion.

Ricketts also was convicted of similar charges in 1978 in Maryland, court records show. Now 64, Ricketts is balding and has a thick, short beard. In court, he supported himself with a cane and wore thick rimmed glasses. During his trial, he spoke quietly with his public defender, Theresa Chernosky, and took frequent notes during the proceedings, which took place before Montgomery County Circuit Court Judge Terrence McGann.

In defending Ricketts, Chernosky said the evidence presented didn’t meet the burden of proof required to convict him.

“The fact that memories fade ... does not lessen their burden,” she told the jury, questioning whether the prosecution could prove that the evidence had not been tampered with over the last three decades, as well as the validity of the DNA evidence.

Ricketts will be sentenced in April. He could face up to life in prison for each of the three convictions.