To neighbors back home in Minnesota, Lois Riess looked like the kind of grandmother you’d trust with your secrets — warm, chatty, quick to laugh. But in the spring of 2018, that image shattered in a case that would earn her a chilling nickname: the “Killer Grandma.”

According to authorities, Riess first turned on the person who knew her best — her husband.

Dave Riess, a small-business owner in Blooming Prairie, was known for his easygoing nature and steady presence in the community. In March 2018, Lois told employees at his worm-farming shop that he wasn’t feeling well and wouldn’t be coming in. Days passed without contact. When a concerned employee requested a welfare check nearly two weeks later, officers made a grim discovery: Dave was dead on the bathroom floor, shot twice in the torso. His body had been covered with a sheet.

By then, Lois was gone.

Investigators soon uncovered financial strain beneath the surface of the marriage. Friends said Lois struggled with gambling and had sought loans from acquaintances. Dave had reportedly intervened, telling others not to lend her more money. After his death, Lois was seen leaving the home in the couple’s Cadillac Escalade.

But Minnesota was only the beginning.

Authorities later learned Riess had traveled south, stopping at a casino along the way and winning thousands of dollars. Eventually, she arrived in Fort Myers Beach, Florida — where she met 59-year-old Pamela “Pam” Hutchinson.

Pam, a recent divorcee, had rented a timeshare condo for a short getaway. Surveillance footage shows Riess striking up a conversation with her at a local bar. The two women talked for hours. They were later seen entering Pam’s condo together.

Only one woman came back out.

Days later, a condo manager checking on a maintenance issue discovered Pam dead in the bathroom. She had been shot in the heart. A pillow with a bullet hole suggested it had been used to muffle the sound. Pam’s identification, credit cards and car were missing.

Outside, investigators found an abandoned Escalade registered to Lois Riess.

Authorities believe Riess targeted Pam because the two women bore a resemblance. With her husband dead and law enforcement closing in, Riess allegedly needed money — and a new identity. Using Pam’s cards, she withdrew cash and fled again, this time driving west.

The manhunt stretched across multiple states. License plate readers tracked her movements through Louisiana and into Texas. Meanwhile, national media coverage spread her face across television screens and social media feeds.

Her run ended in South Padre Island when a restaurant owner recognized her from the news and alerted authorities. U.S. Marshals quietly entered a local restaurant and arrested her without incident. Inside her motel room, investigators recovered two firearms — including the weapon used in both killings — along with Pam’s belongings.

Riess later pleaded guilty to Pam’s murder in Florida and received life in prison without parole. She then returned to Minnesota, where she admitted to killing Dave during what she described as a heated argument. Prosecutors rejected her explanation, and she was sentenced to another life term.

What began as the disappearance of a small-town businessman ended in a cross-country killing spree — carried out by a woman who, to many, once seemed anything but dangerous. The shocking case is once again drawing national attention as it is featured on Oxygen’s Dateline: Secrets Uncovered, revisiting how Riess managed to evade capture for weeks and why her calculated attempt to assume another woman’s identity continues to fascinate true crime audiences today.