Robert K. Tanenbaum is a former Manhattan Assistant District Attorney who now lives in Beverly Hills (he moved to California in 1979 and went into private practice). He served two terms there as mayor and has tried hundreds of criminal cases during a distinctive legal career that began in 1968. Now 70, Tanenbaum has written 28 books, including the DA Butch Karp mystery series. His true crime book, Echoes of My Soul (just out from Kensington), reads like a thriller and is an homage to his three mentors, who tried and presided over the infamous “Career Girls Murders” case that terrorized New York City in 1963 and had a profound impact on the American justice system—and Tanenbaum himself.

Tanenbaum says, “I was trained by homicide bureau chiefs Mel Glass and John Keenan, with District Attorney Frank Hogan, the King Arthur of New York City’s criminal justice department at that time.” He was still in law school at U.C. Berkeley during the trials described in Echoes, which convicted an innocent man for murder and rape before finding the real killer guilty of the crimes. But the case became so notorious that when Tanenbaum went to work for Glass a few years later, it was still being discussed in the DA’s office.

Tanenbaum considers Echoes his most important book. “It’s a story about everything we learned and were supposed to be as criminal prosecutors. Hogan, Glass, and Keenan—they lived it. It’s a thrilling, tempestuous, painful story that I drew on for how to live my life with the set of values involved in the judicial system. It’s immersed in a moral and spiritual philosophy I define as American Exceptionalism.”

It was Tanenbaum’s work as a prosecutor that led him to the man who would ultimately edit and publish his first book, Badge of the Assassin, which was a national bestseller in 1979. Five years earlier, Tanenbaum tried a lengthy murder case and was particularly impressed by the jury foreman—legendary editor Henry Robbins, then with Farrar, Straus and Giroux. When Tanenbaum completed the first 100 pages of Badge—the true account of his investigation and prosecution of the men who assassinated two NYPD officers in the 1970s—he sought out Robbins for advice. But the editor’s last name escaped him. “I phoned FSG and said, ‘I would like to speak to Henry, the editor,’ ” Tanenbaum recalls with laughter. “The receptionist told me that Henry had moved to Simon [& Schuster]. But when I called there, they said he’d quit to become editor-in-chief at E.P. Dutton. At least by then I had his last name!” Robbins was riding high with the success of John Irving’s The World According to Garp in 1978; the following year his bestseller was Tanenbaum’s Badge.

“I’ve had interventions in my life,” Tanenbaum says, “and Henry Robbins was one of them. Echoes is dedicated to him.” (Robbins died just weeks after Badge was published.)

The victims in the Echoes case, Emily Hoffert and Janice Wylie, were young professionals and roommates on Manhattan’s Upper East Side. One morning in August 1963, a man broke into their apartment, brutally raped Wylie and then stabbed both women to death. This was in the days before Miranda Rights, and a suspect who was picked up soon after the murders made a false confession without a lawyer present. He was sent to trial and wrongly convicted. A career criminal was later picked up by the NYPD on an unrelated charge; he told detectives that a friend of his had confessed to the Wylie-Hoffert murders. Cooperating with detectives for a lighter sentence, he helped them shadow the actual killer. When the NYPD had enough evidence, the killer was arrested, tried by Keenan, and convicted.

Four years ago, Glass, who died in 2010, asked Tanenbaum to write Echoes. “He gave me the trial transcripts and the police investigative reports—3,700 pages,” says Tanenbaum. “For those of us who care passionately about justice, this book provides a road map to its achievement.”

DA Hogan was a legend long before the Wylie-Hoffert case. “Once convinced that the wrong man was indicted for the most gruesome murders on the media’s radar, Hogan admitted his mistake,” Tanenbaum says. “This could have fractured his reputation, but Hogan’s priority was to exonerate an impoverished young man with an IQ south of 70. Justice demanded it.” The Wylie-Hoffert case was cited by Supreme Court Chief Justice Earl Warren in 1966 when he wrote the Miranda opinion as an example of why it’s important to have due process in place for suspects. “This is not some Gulag in Russia somewhere,” Tanenbaum says. “If you want a lawyer, we’ll get you one. If you want to remain silent, you can. Because of Mel, John Keenan, and Frank Hogan, we achieved the legal safeguards that protect us today. Echoes of My Soul is my tribute to them.”