WINONA, Minn. -

A 48-year-old Onalaska Middle School band teacher who lives in Winona is facing several assault charges for allegedly threatening to kill the man she's been in a relationship with for 15 years.

On March 19, the victim taped some of the alleged threats using Sandra Kay Kauphusman's cell phone and reported a domestic assault to Winona police.

The criminal complaint states the victim told police their relationship of 15 years was not going well and that Kauphusman "started acting crazy."

During the incident, Kauphusman accused the victim of being a thief and stealing some USB drives, the complaint states. The victim told police he could not leave and that Kauphusman was "holding him prisoner."

Kauphusman walked into the kitchen and picked up a knife, police say the tape shows. The victim asked what she was doing with the knife and asked her to put it down, the complaint states. Police say on video, it looked like Kauphusman did not raise the knife. After putting the knife down, Kauphusman yelled to the victim, "I'm going to kill you," police could see on tape. 

The victim told police he wanted to leave, but Kauphusman was armed with a large wood plank and stood in the doorway and told him he couldn't leave, the complaint states. When the victim tried to get out of the house, she pulled his hair, clothes and scratched his face, the victim told police who also heard the incident on tape.

Before leaving the house, the victim removed the SD card from the phone, went to a store, bought a card reader, downloaded the video to a USB drive and brought them to the law enforcement center, the complaint states. The victim told police Kauphusman had punched him in chest a couple weeks before this incident.

Kauphusman is facing seven charges, including two assault in the second degree charges; two domestic assault charges; two aggravated violations charges; and a charge for terroristic threats-reckless disregard risk. She has been summoned to appear in court on May 30.

In an emailed statement, the Onalaska School District says it "will be investigating this situation immediately.  In the interim, Ms. Kauphusman will be on administrative leave while the investigation is pending.  The District wishes to stress that these steps are being taken in order to be fair to Ms. Kauphusman and to continue to uphold the highest standards of safety for its staff and students. The District will take any steps that are warranted once its investigation is concluded."