A funeral home operator accused of illegally dissecting 569 bodies and selling their parts has been sentenced to 20 years in jail.

Megan Hess, 46, ran the business, Sunset Mesa – and the body parts entity Donor Services – from the same building in Montrose, Colorado, in the United States.

She alongside her mother, Shirley Koch, 69, pleaded guilty to fraud in July. Koch was handed a 15-year sentence, Reuters reported. Federal prosecutors said the mother-daughter duo harvested body parts – and sometimes entire bodies – for sale for use in transplants and medical research.

In a grisly case, Hess charged up to $1,000 for cremations that never took place and offered them for free in exchange for body part donations. Prosecutor Tim Neff said in a court filing:

“Hess and Koch used their funeral home at times to essentially steal bodies and body parts using fraudulent and forged donor forms. Prosecutors described the ‘macabre nature’ of Hess’ harvesting plot and said it was one of the most serious body parts cases in US history. Her lawyer, however, described the case almost as a witch hunt. Hess was not a ‘monster’ or a ‘ghoul’ but a ‘broken human being”.

She was not criminally responsible as her shocking conduct can be traced back to a traumatic brain injury she suffered aged 18. Koch apologised to the judge and took responsibility for her role. District Judge Christine Arguello said yesterday:

“This is the most emotionally draining case I have ever experienced on the bench. It’s concerning to the court that defendant Hess refuses to assume any responsibility for her conduct.”

She ordered the two women to be sent to prison immediately. Those who discovered the body parts of their loved ones had been plundered and sold reacted with horror in court.

Erin Smith, one of 26 victims, told the court, “Our sweet mother, they dismembered her.”

Smith’s mother’s shoulders, knees and feet had been cut out for money. “We don’t even have a name for a crime this heinous,” Smith added.

Tina Shanon, whose mother was also dismembered, said, “I’ve worn so many masks to cover the pain. I’ll never be ok.”

Although it is illegal to sell organs – they must be donated – the selling of cadavers and body parts is a vastly unregulated industry in the US. Thousands of Americans donate their bodies for science – but an underbelly of body brokers flog cadavers and body parts for use in research or education.

No federal laws regulate this, while state laws limiting who can dissect and sell body parts are few and far between. And prosecutors say Kess and Koch embraced this. Not only did the pair cut out hearts, kidneys and tendons, but they also severed heads, arms and spines.

They sold them as well as arms, legs heads and torsos to surgical-training companies and other firms without saying they had been illegally obtained, prosecutors said. Hess and Koch lied to some 200 families – they were handed not their cremated loved ones but the ashes of countless corpses left in bins.

As part of a Reuters investigation from 2016 to 2018 that triggered the federal case, the couple’s funeral business staff described how Koch pulled the gold in crowns or fillings out of the teeth of some corpses. She allegedly cashed the money in for a trip to Disneyland.

Denver FBI special agent Leonard Carollo said, “These two women preyed on vulnerable victims who turned to them in a time of grief and sadness. But instead of offering guidance, these greedy women betrayed the trust of hundreds of victims and mutilated their loved ones.”

• A Reuters report