Longtime local defense lawyer Charles F. Daum was sentenced Tuesday to five years behind bars for his role in a conspiracy to fake evidence and get witnesses to lie in court during a drug trial.

The case rocked the District’s legal community when Daum was charged in 2011. U.S. District Judge Gladys Kessler called the manipulation of the criminal courts one of the most serious nonviolent offenses. If juries and judges cannot rely on the integrity of evidence, she said, “then our system of justice loses its fundamental integrity and the confidence of the public. We all rely on what a lawyer says to us in the courtroom.”

Kessler found Daum guilty in June of masterminding a conspiracy to fabricate evidence and induce perjury in the hopes of helping a client during a 2008 drug trial. Kessler also found Daum’s private investigators — Daaiyah Pasha and her daughter, Iman Pasha — guilty of conspiring to obstruct justice. She sentenced Daaiyah Pasha to three months in jail and her daughter to three years’ probation.

Prosecutors portrayed Daum as an egomaniac who cheated to win and asked the judge to sentence him to 61 / 2 years in prison, the high end of federal guidelines. Daum’s attorney, David Schertler, said his client had already suffered by losing his law license and reputation. He asked for a sentence of one year and a day behind bars.

Even after a month-long trial last year, there was some mystery Tuesday surrounding Daum’s motive for risking his career to help a 28-year-old drug dealer, Delante White, who faced a mandatory 20-year sentence if found guilty on charges of possession with intent to distribute crack cocaine. Daum, 66, has a law degree from George Mason University and started a criminal defense practice in 1994, primarily with court-appointed clients.

Daum declined to address the court before he was sentenced, so it was left to Schertler to paint the picture of a defense lawyer who for years trudged the hallways of D.C. Superior Court, taking difficult cases for troubled clients without any of the resources of a large law firm or government office.

“He went astray and crossed the line in a big way,” Schertler said. “In a bizarre and unjustified way, he felt he was leveling the playing field and helping a young man.”

Justice Department trial lawyer Darrin L. McCullough pointed to evidence admitted, but not proven at trial, that suggested Daum had previously encouraged a defendant to fabricate evidence and said: “This was not the first time he did this. This is the way he did business.”

In her June ruling, Kessler found that Daum directed his investigators, White, White’s family members and his girlfriend to fabricate evidence and lie on the witness stand. The relatives and investigators staged photos designed to show that the drugs had belonged to White’s younger brother. They also faked a lease agreement, Kessler found, to make it look like White was not living at his grandmother’s Northeast Washington apartment, where police seized 124 grams of crack cocaine, cash, a digital scale and a pair of Gucci boots.

The jury in White’s trial deadlocked, and U.S. District Judge Paul L. Friedman declared a mistrial. After prosecutors figured out what had happened, White pleaded guilty to drug dealing, tampering with witnesses and obstruction of justice. He was sentenced to 33 months in prison.

Before announcing Daum’s 63-month sentence to a courtroom filled with lawyers, detectives and friends of the defendants, Kessler said she was sending a message to“all lawyers who may think of cutting a corner or not quite telling the truth to a judge.”