Corey Moore (Sarah L. Voisin/The Washington Post)

Accused of killing three people. Prosecuted in seven trials. Charged 42 times. Hardly any of it stuck to Corey Moore, a District street legend acquitted so many times that he became known as the “Teflon Defendant.”

That is, until Monday, when a federal judge found Moore guilty of serious drug and firearms offenses that will keep him locked up for at least 15 years.

The conviction of Moore, once listed by the FBI as one of the District’s most dangerous people, was a victory 20 years in the making for area law enforcement officials.

“When we find someone who is a repeat criminal, sooner or later we’re going to catch them and hold them accountable,” said Maryland U.S. Attorney Rod J. Rosenstein.

Investigators have thought repeatedly over the years that they had airtight evidence against Moore — only to be thwarted by acquittals or deadlocked juries. Moore and his family maintained his innocence, eventually accusing prosecutors of unduly targeting him out of frustration with their inability to secure a conviction. Moore’s mother, Teresa Richardson, accused prosecutors of carrying out a “vendetta.”

Unlike previous investigations, there were no wiretaps, undercover informants or federal agents involved in the arrest. Instead, the trial at the U.S. District Court in Greenbelt grew out of a routine stop that officials from the small suburban department would later describe as luck.

In September 2010, an officer from the Takoma Park Police Department spotted Moore walking down a quiet residential street with what looked like an open bottle of beer, the patrolman Keith Hubley testified. Moore tossed the bottle into some plants and took off.

Two witnesses testified about the ensuing foot chase and said they saw a plastic bag Moore had been clutching arc in the air toward a trash bin as Moore ran. Authorities later determined that the bag contained nearly a half-kilo of cocaine.

“I have no reason to suspect these neighbors were lying. Why would they lie?” Judge Alexander Williams Jr. said.

“His credibility is just shot with me,” Williams said of Moore. “It’s shot.”

In the basement apartment Moore rented nearby, police found a gallon-size pickle jar under the kitchen sink filled with liquid phencyclidine, commonly known as PCP. In the bedroom closet, tucked among Moore’s clothes, police said they found a brown paper bag containing more than $44,000 in cash and two guns — a loaded .38-caliber revolver and a .44-caliber semiautomatic pistol.

During the five-day trial, there were more than 20 witnesses, including a D.C. narcotics detective, a co-founder of the anti-youth violence group Peaceoholics and even Moore’s landlord. A convicted bank robber testified about investing in a documentary on Moore’s harassment over the years by the criminal justice system.

Prosecutors portrayed Moore as a sophisticated drug dealer who tried to stay off the grid by concealing his address, operating with large amounts of cash and frequently changing his cellphone number.

“It almost worked for Mr. Moore,” Assistant U.S. Attorney Steven E. Swaney said in his closing argument Monday.

At 5-foot-5, Moore was known as Li’l Corey growing up in Southeast Washington in the 1980s. Moore’s former attorney described him as personable and charming, and he had a good track record with jurors in the District.

On trial for the first time in Greenbelt, Moore and his defense lawyer took a different tack: a trial without a jury. Moore also told his story from the witness stand for the first time since 1994.

Moore, 37, and his defense attorney, Brian K. McDaniel, suggested that the drugs and firearms found in the basement apartment were planted there by police who had Moore’s house keys in the days after his arrest.

Moore was not in the Sherman Avenue apartment at the time of the search and there were no fingerprints, no DNA evidence nor surveillance to tie him to the firearms or the drugs found.

“We don’t know how, when or by whom those items got into this location,” McDaniel said during the closing argument. “There are too many questions the government has not answered.”

On the witness stand, Moore also testified that he previously had been harassed and threatened by the Takoma Park police officer who arrested him.

But Williams, serving as judge and jury, said Monday that Moore’s testimony directly contradicted neighbors and the police officer who said he had never seen Moore before the day of his arrest.

Williams also said he was skeptical of testimony from two of Moore’s friends who said they had provided the cash found in the bag to help fund the documentary film.

Before the trial began last week, prosecutors spelled out Moore’s arrest record in court papers, ticking off 42 total charges from 1992 to 2004: murder, armed robbery, assault, carrying a pistol without a license, obstructing justice, counterfeiting, conspiracy to sell heroin, cocaine and PCP, fleeing and eluding. Nearly all ended with Moore coming out on top, with either charges dismissed or trials won.

The case that made him notorious among law enforcement officials began in 1994. Moore was tried four times over four years in the District in the killing of Byron Hammon, who was shot while sitting in his car. Four times, jurors deadlocked, and prosecutors eventually dropped the charge.

One exception came in 1995, when Moore was sentenced to 51 months in prison after law enforcement officials found a sawed-off assault rifle, hunting knife, flak jacket and gas mask hidden in his closet.

According to the Maryland U.S. attorney’s office, Moore faces a minimum sentence of 15 years on two of the four counts in this case — possession with intent to distribute PCP and possession of a firearm in furtherance of drug trafficking. The two additional counts, possession with intent to distribute cocaine and being a felon in possession of guns and ammunition, could lead to additional prison time.

A fixture at all of Moore’s trials has been his mother. Outside the courtroom on Monday, Richardson said she had hoped for a different outcome. “What can I do but be strong and go on?” she said.

Moore’s sentencing is set for May. His attorney said he would appeal.