Riess, described as a five-foot-five, 165-pound woman with brown eyes and blonde hair, was already accused of killing her husband, David, in Minnesota last month — then going on the run across the country. Police say she eventually ended up in Ft. Myers, on Florida's Gulf Coast, where she found 59-year old Pamela Huchinson.

The two, seen together at a Ft. Myers Beach restaurant, became friends.

"This stone-cold killer was smiling like anyone’s mother or grandmother when she approached our victim,” Marceno said.

But authorities said Riess had an ulterior motive — planning all along to steal Hutchinson’s identity because the two women looked so similar.

"This is the first time in my career that I’ve seen someone steal someone’s identity and target them for the way they look, in order to murder them," Marceno said.

Investigators said surveillance video shows Riess at Hutchinson's condo and that after killing her, Riess took Hutchinson's credit cards and license and stole her white Acura, which was spotted in Louisiana and Texas, according to police.

"The Dodge County Sheriff’s Office and Dodge County Attorney’s Office are preparing second-degree murder charges against Lois Riess for the March 2018 murder of her husband David Riess," the Minnesota Bureau of Criminal Apprehension wrote in a Facebook post. "Investigators believe Pamela Hutchinson may have been killed with the same firearm used to murder David Riess. Investigators are not aware of any connection between Lois Riess and Hutchinson."

Authorities said Reiss is considered armed and dangerous, warning that her killing spree may not be over.

“At some point in time (she) will have no resources,” Marceno said. “And she will become more desperate and may kill again.”