Sarah Anne Wierstad had no clue what she was walking into Sunday night when she opened the back door of her home on St. Paul's East Side.

But when she flipped on the lights, she stumbled onto a frightening scene — three men rummaging through her house in an apparent random burglary.

They pointed a gun at her and ordered her to her knees, stealing her purse, among other belongings, according to a criminal complaint filed Friday in Ramsey County District Court.

As they started to flee, they ordered her to stay down. When she followed out the door to ask for her phone back, one of the men hollered, "Stay back. Stop following us." Seconds later, after trying to reason with the men by telling them that her daughter was on the way home, Wierstad was fatally shot.

One bullet struck her left foot. Another ripped through her arm and heart, killing her shortly before 8 p.m. just steps from her home in the Railroad Island neighborhood.

Two men — Alvin R. Bell and Isiah L. Harper — have been arrested and charged in the case and a third, known only as "AB" in charging documents, is being sought by authorities.

Harper, 26, of Minneapolis, was charged with first-degree aggravated robbery and first-degree burglary. Details of the burglary and what Wierstad said and was doing moments before she was shot were contained in the complaint.

A day earlier, Bell, 24, residence unknown, was charged with second-degree murder with intent.

The case remains under investigation, and it's still unclear who shot Wierstad, said Erica Schumacher, director of strategic initiatives and community relations for the county attorney's office.

The charges against Bell imply that he was the gunman, while the charges against Harper state that Harper was sitting in the getaway vehicle when he "saw AB go back and heard 4 to 5 shots. AB then ran back into the vehicle."

Schumacher said that Bell and AB are different people, and that AB's identity and whereabouts remain under investigation.

A random burglary

Harper spoke to police after his arrest, but he gave "several different accounts" of what happened, the charges against him said.

Meanwhile, forensic evidence tied Bell's fingerprints to one of Wierstad's windows, and surveillance video later showed him using her credit card at a gas station, the charges against him said.

Bell didn't say anything about the robbery or shooting in his interview with police. He told an investigator that someone gave him the credit card. The interview was later terminated when he asked for an attorney.

According to the complaint against Harper: The men selected Wierstad's apartment at random. Bell and AB entered to look for items. Bell called Harper to the front of the apartment so he could hand over stolen items.

The men heard a noise from the back of the apartment, and then a light flicked on. Wierstad appeared, and AB pointed a gun at her. Harper first told police that Bell ordered her to the ground, and then said AB issued the order.

"She was on her knees, and AB and Bell were talking back and forth," the complaint said.

Harper told police that Bell grabbed Wierstad's purse from her shoulder. Harper then ran out the front with the other stolen items. Harper told police that he heard AB order Wierstad to stay on the ground until the men left.

But once "they" got to the vehicle, the complaint said, Harper heard the exchange between Wierstad and AB about the phone and Wierstad's daughter, and then gunshots.

Wierstad was found on the sidewalk by neighbors who rendered aid and called for help. She had just returned home from a 12-hour shift as a cook at the Alton Memory Care assisted living center in St. Paul.

Wierstad's 5-year-old daughter was in the care of her paternal grandmother and was due home shortly.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib