In the middle of the night last September, a witness in a fraud case stepped outside her brother’s Shoreview apartment for a smoke.

A car sped into the building’s lot, catching her off guard, according to court papers. The suspect, an old acquaintance nicknamed “Smelly,” exited the SUV and rushed at the 20-year-old woman, yanking her backward by her hair and flashing a knife.

A career criminal on an alleged east-metro crime spree, he shoved the woman into the SUV, driven by his cohort, according to charges against Brian J. Mehlhorn, 30, of Oakdale.

What happened next, court papers say, was a beating as Mehlhorn tried to influence her testimony in his pending fraud case, a knife fight as he stabbed his getaway driver, and the woman’s terrified flight through suburban yards until she found a good Samaritan.

Those allegations were outlined in a complaint filed Thursday in Ramsey County against Mehlhorn, who landed in St. Cloud prison three weeks ago for auto thefts and burglaries he committed in Washington County.

The complaint charges Mehlhorn with kidnapping the witness. Her ordeal unfolded this way, according to the court papers:

The woman’s brother picked her up from work on the evening of Sept. 5. In the early-morning hours of the next day, she stepped out for a cigarette in the parking lot at 3541 Owasso St. in Shoreview.

Once Mehlhorn shoved the stunned woman into the accomplice’s back seat, he snatched her cellphone and purse. He slapped her and punched her in the forehead, making her nose bleed.

Mehlhorn and his partner, identified in court papers as Dan Callihan, 30, questioned her about information she had given police about the suspect, whom officers knew only as Smelly until she disclosed his real name and the kind of car he drove.

Mehlhorn kept hitting and slapping the woman, telling her that she needed to cooperate with him and his lawyer.

“He wanted her to lie and testify in a certain way,” the complaint states.

The suspects pulled the SUV into a White Bear Lake gas station and got out, leaving a door open. The woman bolted for the gas station, but they forced her back into the SUV and drove around more.

Soon, Mehlhorn and Callihan began fighting about some stolen Twins tickets and got out of the car in Oakdale. Mehlhorn allegedly stabbed Callihan.

The young witness fled, running through back yards, until she found a good Samaritan who let her use his cellphone. Glancing about in fear, she called her brother, crying that she’d been kidnapped and beaten. He called 911.

With a stab wound to his abdomen, Callihan drove to Regions Hospital in St. Paul. He’s been cooperating with investigators.