Two assistants who worked at the practice testified that they did not know Ms. Magbanua to be an employee . A few months after the murder, Ms. Magbanua paid a plastic surgeon $4,000 in cash for breast implant surgery.

In April 2016, police tapped the cellphones of Mr. Garcia, Ms. Magbanua, Charles Adelson and Donna Adelson. To get them to talk to one another, an undercover F.B.I. agent posed as a member of the Latin Kings gang and asked Donna Adelson for more compensation for the family of Mr. Rivera, who was in prison. Mr. Garcia was arrested the following month, and Ms. Magbanua some months later.

None of the Adelsons have been charged. For years, as Mr. Markel’s sensational murder has been dissected in news articles, blog posts, a popular true-crime podcast and episodes of “Dateline” and “20/20,” lawyers for the Adelsons have maintained their innocence.

Donna Adelson, 69, had figured prominently in her daughter’s divorce. About a year before the murder, she suggested that her daughter pretend the couple’s sons had converted to Catholicism — Mr. Markel was an observant Jew — to pressure Mr. Markel to agree to the children’s relocation. Donna Adelson also floated offering Mr. Markel $1 million to allow the move.

The day of the shooting, the police brought in Wendi Adelson, 40, a former clinical law professor at Florida State, to tell her what had happened to her ex-husband. She cried and buried her face in her hands, according to police video of the interview. She also mentioned that her brother, after buying her a television as a divorce present, had joked, “I looked into a hiring a hit man and it was cheaper to get you this TV.”

“But he would never,” Ms. Adelson added. “It’s such a horrible thing to say.”

Wendi Adelson testified at the trial that she had no knowledge of the murder. She moved her sons to South Florida a few days after Mr. Markel was killed.

Ms. Magbanua took the rare step of testifying in her own defense. She said she began receiving the checks from the Adelsons after she asked Charles Adelson to hire her as his assistant — a favor so she could qualify for state health insur ance for her children. The money for her surgery, she added, had been saved up from cash tips she made working in nightclubs.