Blake Leibel was convicted of torturing fiancée Iana Kasian to death in 2016

The graphic novelist convicted Wednesday of torturing his fiancée to death was motivated by jealousy over the attention she paid to the couple’s infant daughter, a spokeswoman from the Los Angeles County District Attorney’s Office tells PEOPLE.

Blake Leibel, 37, was convicted of multiple felonies including mayhem and torture in the death of his fiancée Iana Kasian in May 2016.

Kasian was found dead in the couple’s West Hollywood, California, apartment on a bed, drained of her blood. Her scalp had been removed.

Her autopsy results from the Los Angeles County Coroner’s Office showed that she died of blunt force trauma to the head, according to Fox News. She also had portions of her face torn off.

Three weeks earlier, Kasian had given birth to the couple’s daughter, Diana, according to the Los Angeles Times.

During the trial, prosecutors revealed Kasian’s grisly death stemmed from Leibel’s jealousy and anger over the baby as well as his need for power and control over his fiancée, the spokesperson tells PEOPLE.

Before the baby was born, Kasian’s mother flew from Ukraine to help welcome the newborn, Deputy District Attorney Beth Silverman said in court. But Leibel didn’t want Kasian’s mother, Olga, to be present for his daughter’s birth and soon he and Kasian began to grow apart. After the birth, Kasian began to spend more time at her mother’s apartment, Silverman said, according to the Toronto Sun.

“What happens after the baby comes home? Within four days, she’s out. She can’t stay in the apartment with him,” Silverman told the jury. “He’s jealous because now the baby’s in the picture and it’s taking away his attention.”

Silverman continued: “What is the ultimate act of power and control? It’s taking somebody’s life, right? Taking away their future. Taking away everything they dreamed they were going to be: A mother, a parent, a daughter, a wife.”

From left: Blake Leibel and Amanda Braun
| Credit: BILLY FARRELL/Patrick McMullan via Getty; Facebook

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Iana Kasian
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Leibel, who was a budding filmmaker and graphic artist, is the son of one of Canada’s wealthiest real estate developers and one-time Olympic sailor Lorne Leibel. He was reportedly living on an $18,000 a month allowance, according to the Associated Press.

Leibel is best best known for his 2010 graphic novel Syndrome in which a scientist experiments on a serial killer in order to find a cure for evil. The killer murdered a man by slitting his throat and hanging him by his ankles so he bled out.

Silverman told jurors that Syndrome served as a “blueprint” for Leibel in Kasian’s “very slow, excruciating, painful” death, the Times reports.

Leibel will be sentenced on June 26 and faces the possibility of life in prison, according to the Times.