Updated at 5:52 p.m.: Revised to include additional background.

A Dallas jury sentenced a neurosurgeon to life in prison after it heard from over a dozen patients who testified Christopher Duntsch seriously maimed them while they were under his knife.

Christopher Duntsch (Dallas County Sheriff's Department)

Duntsch, who practiced medicine at various hospitals in Dallas and Collin counties, was accused of crippling four patients and causing the deaths of two others between July 2012 and June 2013.

The 46-year-old was arrested in July 2015 on five aggravated-assault charges.

His 13-day trial in a Dallas County courtroom focused only on a charge of injury to an elderly individual — a first-degree felony where someone "intentionally, knowingly, recklessly, or with criminal negligence" injures an elderly person.

That victim, Mary Efurd, was 74 in 2012 when she went under Duntsch's knife and lost a third of her blood and the full use of her legs.

"I trusted him," Efurd testified three weeks ago. "I trusted that he would do what was right."

But a doctor who treated Efurd after her botched surgery said Duntsch had "done virtually everything wrong." Dr. Robert Henderson found implants placed in muscle instead of on bone, a screw drilled into her spinal cavity and a nerve root that had been amputated.

"It's as egregious as you can imagine," Henderson said.

Jurors heard from patient after patient who sought surgery from Duntsch to fix back problems, only to be left disfigured or immobilized and in excruciating pain.

They heard from Philip Mayfield, who cries when he thinks of all of his son's football games that he hasn't been able to watch because he often passes out from chronic pain, and Barry Morgaloff, who limps with a brace and a cane as a result of irreparable nerve damage in his spine.

They heard from Jeff Cheney, who woke up paralyzed from the neck down on his right side, and Jackie Troy, who talks in a permanent whisper and almost died from an infection after she was left with puncture wounds in her throat after Duntsch performed neck surgery on her.

"I'm just trying to stay focused and be thankful that I'm one of the lucky ones in this situation," said Troy, who's alive to talk about her encounter with Duntsch, unlike two of his patients: Kellie Martin and Floella Brown, who died after undergoing back surgery in 2012.

Duntsch's lawyers said he was "not a skilled surgeon" and had been distracted by a chaotic operating room. "He was on his own and doing the best he could," defense attorney Robbie McClung said.

Prosecutors, however, argued that Duntsch had years of training and knew exactly what he was doing during his botched surgeries.

"He chose not to get help," prosecutor Michelle Shughart said. "He chose to continue maiming and killing patients."

In Brown's case, he removed "bone from an area that was not required by any clinical or anatomical standards, resulting in injury to the vertebral artery," according to Texas Medical Board records.

Prosecutors also pointed to an email Duntsch wrote in 2011, in which he said that he was ready to "become a cold blooded killer."

Martin's daughter, Caitlin Martin-Linduff, said she was relieved by the jury's decision.

Joe Brown, Lorraine Brown, Don Martin and Caitlin Martin-Linduff with a painting of Kellie Martin. (Caitlin Martin-Linduff)

"It won't obviously bring my mom back and it won't heal the 34 people that have been affected, but it will bring some sense of justice and particularly some sense of closure," Martin-Linduff said.

During a break in testimony Monday, Brown's family presented the Martin family with a hand-painted portrait of Kellie Martin done by one of their family members.

"We've become almost like a family," Martin-Linduff said of Duntsch's patients and their relatives. "It helps to be able to grieve alongside them and know we're not alone."

Staff writers Jennifer Emily and Tom Steele contributed to this report.