A former funeral home owner and her mother were sentenced on fraud charges related to the selling of body parts. Tuesday’s 20-year sentence for 46-year-old Megan Hess, operator of Sunset Mesa Funeral Home in Montrose, Colorado, was the maximum allowed under law.

Her mother, 69-year-old Shirley Koch, was sentenced to 15 years in prison. Both of their sentences came following guilty pleas to charges of mail fraud and aiding and abetting.

“According to the plea agreement, from 2010 through 2018, [Hess] and others stole the bodies or body parts of hundreds of victims, and then sold those remains to victims purchasing the remains for body broker services,” the U.S. Attorney’s Office for the District of Colorado said in a news release. “Koch was involved in meeting with families seeking cremation services for their loved ones who had died.”

While it is illegal in the United States to sell organs such as hearts, kidneys and tendons for transplant; selling body parts such as heads, arms and spines for use in research or education is not regulated by federal law. Where Hess committed crimes – according to prosecutors –  was when she charged relatives of the deceased up to $1,000 for cremations that never happened.

Families received cremated ashes from bins mixed with the remains of different cadavers than their loved ones. Prosecutors said Hess lied to more than 200 families and dissected 560 corpses.

“The defendants’ conduct was horrific and morbid and driven by greed. They took advantage of numerous victims who were at their lowest point given the recent loss of a loved one,” U.S. Attorney Cole Finegan said in a statement. “We hope these prison sentences will bring the victim’s family members some amount of peace as they move forward in the grieving process.”

Prosecutors described the funeral home case as one of the most significant body parts cases in recent U.S. history. During Tuesday’s sentencing, U.S. District Judge Christine M. Arguello described it as “the most emotionally draining case I have ever experienced on the bench.”

Reuters contributed to this report.