A Brooklyn man whom prosecutors decribed as a "modern-day gangster" was convicted in Alexandria federal court yesterday of conspiring with other New Yorkers to run an Old Town crack house where a police officer was killed.

A jury took four hours to find Theodore Henderson III guilty of 10 criminal charges, including conspiracy, racketeering, drug possession and illegal use of a weapon. Henderson, 19, faces a possible prison term of life without parole and will be sentenced Nov. 30.

Henderson and three conspirators were indicted last spring in connection with events that led to the slaying of Cpl. Charles W. Hill by a gunman hired for $200 to collect a drug debt in an Old Town housing project.

Jamie Martin Wise, who robbed the occupants of an apartment in the 300 block of Hopkins Court before he took them hostage, fatally shot Hill in the face with a sawed-off shotgun before he was gunned down by police.

Officer Andrew Chelchowski, who was wounded in the shooting and provided key testimony in the two-day trial, said the verdict "does add some sort of relief, but you can't take away the suffering people have gone through in the last year and a half."

Hill died trying to save the life of Eddie Jackson, Wise's last hostage. Jackson later was convicted and sentenced to 20 years in prison for managing a crack ring out of the Hopkins Court apartment where Wise was sent to collect a $3,800 crack debt from Jackson.

Assistant U.S. Attorney Liam O'Grady described Henderson and his partners as greedy gangsters who came to Alexandria because potential drug profits were high there and the police presence was less than in New York.

"They found the land of opportunity in Virginia in mid-February last year, and they found a crack house where they could work," O'Grady told the jury in his closing statement. " . . . They had nirvana, and they were willing to do anything and everything to keep that nirvana."

O'Grady emphasized that federal conspiracy laws hold Henderson, as a member of the drug ring, responsible for all the crimes committed by the group.

"They stored their drugs together, they stored their weapons together . . . they fought together," O'Grady said.

In attempting to show the jury that Henderson displayed a pattern of violence, prosecutors presented evidence that he was involved in another incident the day before Hill was killed.

According to testimony Tuesday, Henderson and a conspirator got into a brawl near the Houston Recreation Center on Alfred Street in North Alexandria the day before Hill was slain. After being badly beaten, Henderson and others retrieved a rusty .45 caliber handgun from a house in the District and returned to Alexandria to take revenge, witnesses testified.

Eric McCormick, convicted earlier this year for his role in the conspiracy, said the fight flared over a $75 drug debt. McCormick added that when Henderson saw his intended victim "down at 'the strip' down by the Rec Center . . . he pulled out the gun and started firing."

Jackson accused Henderson of waving a rusted handgun in his face and ordering him to pay his debt to another New Yorker.

James C. Clark, Henderson's attorney, attacked the credibility of the witnesses, most of whom are serving long sentences on drug charges. These were "big-time, brutal drug-dealing people" trying to reduce their prison terms by pinning the blame on Henderson, Clark argued.

"The evidence shows very clearly that he was set up. Don't let them drag you into their abyss," Clark urged.