Therese Klotz was only supposed to stop by a friend's house "for a sec" when she was struck and killed by an unidentified driver Friday night.

Klotz, 53, was the latest victim in a string of St. Paul hit-and-runs in the past few months. As of Monday afternoon, police had yet to arrest a suspect in her death. The cases are not related.

"We're just going to be here for a sec," Dorothy Brown remembered her friend saying. But in the next moment, Klotz was down on the street.

Klotz, of St. Paul, died at Regions Hospital after being hit by a sports-utility vehicle as she was standing outside her car in the 700 block of Randolph Avenue about 6:40 p.m. Friday.

Police said that Klotz had just parked in front of a home and stepped out of the car on the traffic side of the street. She was talking to Brown, whom she had driven home before going out together for pizza, when Brown heard a thud.

Brown, who was facing her house, said she thought that Klotz had just dropped her purse. However, when she turned around she spotted her friend in the street and saw the SUV driving east on Randolph Avenue and eventually turn north on W. 7th Street toward downtown St. Paul.

Police found a silver right mirror cover, possibly from a 2005 or newer Lexus or similar vehicle, at the scene. Police plan to check images from security cameras at businesses in the area.

It was dark and Klotz was wearing dark clothes so it's possible that the driver didn't see her, but still should have stopped, Brown said.

"I just don't understand how this person can live with [himself or herself]," said Brown, 59.

Flowers decorated a tree Monday outside of Brown's home near where Klotz was killed. Klotz was always trying to help someone, Brown said.

Klotz often would bring food to people who needed it, said Tom Mason, her longtime boyfriend. "She was a very giving person. … That's just the way she was," he said.

Klotz was born and raised in St. Paul and attended Highland Park High School, he said. She was the youngest of three girls and a boy in her family, Mason said.

Klotz had been on disability for the past 20 years after she injured her back lifting a package of coins during her work at a bank, Mason said. The couple had lived together for the last dozen years.

Mason described Klotz as an outgoing person who enjoyed spending time with friends.

"Whoever killed her should turn themselves in," he said. "To do that to somebody, I don't care if they were drunk or whatever, they still have to 'fess up to that."

Last month, 31-year-old Wade Souster was found unconscious at the intersection of Phalen Boulevard and Atlantic Street after being struck by a hit-and-run driver. He is being treated for brain injuries, pelvic and facial fractures, bruised lungs and a broken leg. Police are still looking for suspects.

In September, 92-year-old Roy Kromschroeder was riding his motorcycle to the mall for his daily walk when he was struck and killed by a hit-and-run driver at Prosperity and Ivy avenues. A 26-year-old woman has been charged in his death.

Anyone with information about Klotz's death is asked to call the St. Paul traffic investigations unit at 651-266-5582.

Nicole Norfleet • 612-673-4495

Twitter: @stribnorfleet