FORT MYERS, Fla. -- A tip-off led to the arrest in Texas of Lois Riess, a woman who investigators believe killed her husband in Minnesota. She then fled to Florida, where she fatally shot her doppelganger with the intention of assuming her identity, the U.S. Marshals Service said Friday. Two federal deputy marshals arrested Riess, 56, about 8:30 p.m. Thursday at a restaurant in South Padre Island, Texas, the agency earlier said in a statement.

South Padre Island is a beach resort community 27 miles from the crossing into Mexico.

City spokeswoman Angelique Soto said Friday that a witness called authorities saying a woman matching Riess' description was at the restaurant. Her identity was confirmed by officers and the car she was using was towed and impounded "for forensic processing," Soto said. It was the same car she had allegedly stolen in Florida, Dodge County, Minnesota sheriff Scott Rose said.

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At a press conference Friday morning in Florida, Deputy U.S. Marshal John Kinsey told reporters that Riess was taken into custody without incident. South Padre officials said she wasn't armed.

Lois Riess mugshot, taken on April 19, 2018 South Padre Island (Texas) police

According to deputies in Texas, Riess wasn't surprised when she was caught, Kinsey said.

"She knew it was coming," he said, noting the news coverage the manhunt had received.

Even though Riess was arrested so close to the Mexican border, Kinsey said there were no indications that she was trying to flee the country.

Carmine Marceno, the undersheriff in Florida's Lee County, where one of Riess' alleged victims was found dead, said detectives were working to get Riess extradited to the state.

"Today's a huge win," Marceno told reporters. "She can't strike again. That was our main concern. We ran a killer off the streets."

Riess had been on the run since at least late March when her husband, 54-year-old David Riess, was found fatally shot at their home in Blooming Prairie, Minnesota. She became the subject of a nationwide hunt.

She had been seen on March 23 at a convenience store and casino in northern Iowa. Authorities released video showing Riess approaching the store cashier, buying a sandwich and asking for directions south of the state. The store is next to a casino where authorities say Riess spent the day gambling before stopping at the gas station.

It was also on March 23 that David Riess' business partner called authorities to ask them to check on him. The partner said no one at work had seen David Riess in more than two weeks. Authorities found David Riess' body inside his home with multiple gunshots.

They were not able to determine how long he had been dead and could not find his wife. They learned Lois Riess may have been at the casino in Iowa, but she wasn't there when they went looking for her.

From there, investigators believed she went to Florida where she killed 59-year-old Pamela Hutchinson of Bradenton, Florida.

Authorities were called to Fort Myers Beach on April 9 and found Hutchinson dead, with gunshot wounds. Investigators believe Riess used the same gun to kill her husband and Hutchinson, and that she killed the woman to assume her identity.

Surveillance video showed Riess smiling and talking with Hutchinson on April 5 at a brewery in Fort Myers Beach. Authorities say she may have targeted Hutchinson because the two women looked alike.

Hutchinson had moved to Florida last year from Virginia Beach, Virginia.

Scott Rose, the sheriff of Dodge County, Minnesota, said at a press conference later Friday that that both Riess' and Hutchinson's passport information had been flagged to border authorities, so it was unlikely she would have been able to cross into Mexico. He thanked the media and said the publicity helped lead to Riess' arrest.

"From a media standpoint, we couldn't have done this without you guys," Rose said. "The amount of coverage we had nationwide is why she was arrested last night."

Rose said he was "relieved" to learn of the arrest in Texas.

"We were concerned for the public's safety because of her actions in Florida and obviously there was a concern about her coming back here as well," Rose said.

Riess is being held in the South Padre Island jail. Rose said it was likely Riess would first be extradited to Florida, because charges there have already been filed. He said prosecutors in Minnesota and Florida were working together to coordinate prosecution.

Minnesota court records show that Riess was suspended as guardian for her disabled 61-year-old sister after a report that she had been transferring funds from a guardianship account to her own account, then withdrawing funds at a casino.

A 2015 affidavit said thousands of dollars had been spent at Diamond Jo Casino in northern Iowa, not far from Riess' Blooming Prairie home. Riess was never charged with a crime, but was ordered to pay her sister more than $100,000.