“It is startling what the dead have to say” – and crime novelist Patricia Cornwell proves it in her new nonfiction book.

“Portrait of a Killer: Jack the Ripper – Case Closed” is the product of 18 months of research to prove that the unidentified murderer of at least seven prostitutes in 1888 London was a respected young artist named Walter Sickert.

Cornwell examines the murder spree, which terrified London’s East End between August and November, using modern investigative and forensic techniques. She offers DNA evidence from alleged Ripper letters to the police, Sickert’s artwork, historical accounts of the artist’s behavior and analyses of crime scene investigations to uncover what she calls the “naked truth.”

Cornwell does more than point the finger at Sickert. She brings the names and lives of the Ripper’s victims to the forefront, frequently taking the limelight away from an egotistic killer who, her research suggests, probably would relish the fact that a book about his crimes had been written more than a century later. She reminds readers that Mary Ann Nichols, Annie Chapman, Elizabeth Stride and other victims were real women forced into prostitution by poverty and alcoholism, then viciously slaughtered, some beyond recognition.

Cornwell’s suspect was an established painter who rubbed elbows with the Victorian era’s artistic and literary celebrities and studied under the American artist James McNeill Whistler. The first of his three wives, Ellen Cobden, was the daughter of a prominent British politician who believed in women’s rights.

Born in Germany, Sickert was a man of disguise and contradiction, according to Cornwell. He was an aspiring actor who used aliases and was known to disguise himself with clothing, false beards and hairstyles.

His trickery also carried over into his personality. Cormwell writes: “One piece of Sickert was kind to his drug-addicted, weak brother Bernhard, while another piece thought nothing of appearing at the Red Cross hospital to sketch soldiers suffering and dying, and then ask for their uniforms since they wouldn’t be needing them anymore.”

Cornwell suggests that Sickert’s murderous behavior and morbid art could have been a psychological consequence of, among other influences, a genital birth defect. The disfigurement forced him to have three painful operations :quot; exacerbated by the old-fashioned medical procedures :quot; and probably left him unable to perform sexually.

Cornwell shows Sickert as a 5-year-old on his way to the hospital sitting next to a cold-hearted father “who wasn’t the sort to hold little Walter’s hand and offer words of love and comfort.”

This pitiable little boy became an adult who, according to Cornwell, called women “bitches,” spent nights in music halls sketching severed body parts, painted murder scenes and a work titled “Jack the Ripper’s Bedroom” and, worst of all, disemboweled prostitutes.

Cornwell also describes the rudimentary investigative skills of the London police force during that time and suggests how today’s investigators with modern technological capabilities would have handled the case.

“Portrait of a Killer” reaches beyond the sensationalism and wonder that has long followed Jack the Ripper and invites readers to look below the surface and beyond the facades, and listen to the dead.