When David Wilson was 12 years old, he became friends with Howard Venable Jr., a then 62-year-old District man who worked as a security guard.

Venable’s family say Howard Venable took an interest in the young Wilson and tried to serve as a mentor. But Wilson’s attorney and D.C. police detectives say at some point, the relationship turned sexual and Venable paid Wilson for sex.

On Feb. 1, 2013, D.C. prosecutors said that the relationship turned violent and Wilson orchestrated a plan to rob Venable in his Northwest Washington apartment. In the course of the robbery, prosecutors said Venable was killed. His throat was slashed, they said, and he was stabbed repeatedly in his upper body. Wilson, 22, was charged with second-degree murder in the 72-year-old man’s death.

On Friday, after pleading guilty to voluntary manslaughter earlier this year, Wilson was sentenced by a D.C. Superior Court judge to nine years in prison, a sentence that prosecutors and Wilson’s public defender agreed upon as a result of the plea deal.

“I really struggled with this plea,” Judge Jennifer Anderson said. A nine-year sentence, she said, “didn’t seem adequate for taking a life.”

The judge also gave Wilson five years of supervised probation after his release.

At Wilson’s sentencing Friday, Venable’s adult daughter spoke of how Wilson had attended family gatherings with Venable at her home. “You have been to my house. You have broken bread with us,” she said.

Several family members said they were disappointed with the sentence. In an interview, Venable’s brother, George Jones, said nine years “wasn’t enough.”

Before he was sentenced, Wilson apologized to Venable’s family. “I wish I could go back and change everything. I need help. I hope one day you can actually forgive me.”

During Wilson’s preliminary hearing last year, a D.C. homicide detective testified that Wilson and at least one other witness told authorities that the two men were involved in a relationship in which Venable would pay Wilson for sex every two weeks. Hours before Venable was killed, one witness told authorities, the men were exchanging text messages about Wilson bringing over “ice cream.” That, the detective said, was code for sex.

Until a few days before Venable’s death, according to testimony at that hearing, the two lived together in Venable’s apartment in the 1600 block of Fuller Street NW on the edge of Adams Morgan and Mount Pleasant.

Prosectors declined to comment on the alleged sexual relationship between the men.

Prosecutors said Wilson did not stab Venable but that he was present when at least one of the two other individuals he was with did the stabbing. Anderson asked about the status of the two other suspects. Assistant U.S. Attorney Holly Shick declined to respond in open court, but at a bench conference, she gave a brief update on the case. She later said that Wilson planned the robbery.

Prosecutors said that hours after Venable’s death, Wilson made three separate withdrawals with Venable’s ATM card, totaling $600.

Wilson’s attorney, Jacqueline Cadman of the D.C. Public Defender Service, called the relationship between her client and Venable “complicated and unfortunate.”

After the sentencing, Venable’s family members declined to comment as they exited the courthouse.

Get updates on your area delivered via e-mail