A La Crosse college professor, Matthew Sierra, has been charged with killing 27‑year‑old Alexis Pickett and their unborn child and allegedly setting her apartment on fire to cover up the crime. Investigators say medical examiner findings show Pickett was dead before the blaze, and surveillance footage reportedly places Sierra at her apartment the night of the killing. Witnesses told police Sierra had pressured Pickett to have an abortion and threatened custody of their son if she refused. Sierra faces homicide, arson and animal mistreatment charges and is due in court on Dec. 23.
Wisconsin Professor Charged With Killing Pregnant Mistress and Their Unborn Child, Allegedly Set Apartment Ablaze
La Crosse Police Department; City of La CrosseMatthew Sierra (left); Alexis Pickett
A La Crosse, Wisconsin, college professor has been charged after a woman with whom he allegedly had a years‑long extramarital relationship was found dead in an apartment fire.
According to a criminal complaint obtained by PEOPLE, 27‑year‑old Alexis Pickett was pronounced dead at the scene after firefighters responded to a blaze at her La Crosse residence on Nov. 13. A dog was also discovered dead inside the apartment. An autopsy later concluded Pickett had been killed before the fire was started.
City of La CrosseAlexis Pickett
Allegations and Arrest
Police say 38‑year‑old Matthew Sierra, a married college professor who admitted to an affair with Pickett, is accused of killing her and their unborn child and then attempting to conceal the crime by setting the apartment on fire. Sierra was arrested on Dec. 17 and faces multiple charges, including first‑degree intentional homicide, first‑degree intentional homicide of an unborn child, arson and animal mistreatment.
What Investigators Found
Investigators cite a mix of witness statements, surveillance footage and medical examiner findings. The Southeast Minnesota Regional Medical Examiner’s Office reported that Pickett was "deceased prior to the fire," noting a lack of soot in her lungs and no carbon monoxide in her bloodstream.
La Crosse Police DepartmentMatthew Sierra
"All I know is that they have been on and off and they have been constantly fighting because he found out she was pregnant with his kid and he didn’t want anything to do with it," a friend of Pickett told investigators, according to the complaint.
The friend also said Sierra had pressured Pickett to have an abortion and allegedly threatened to seek full custody of the couple's son if she refused. Pickett had publicly announced her pregnancy on social media.
Surveillance and Timeline
Although Sierra’s wife told police she believed he was at home the night of the killing and that his phone remained at their residence that evening, surveillance footage cited in the complaint reportedly shows Sierra entering and exiting Pickett’s apartment and leaving just as the fire began to spread. The complaint also states Sierra remained a short distance away in his car until smoke alarms in the building could be heard in video evidence.
Legal Status
Sierra has denied involvement in the killing while acknowledging the affair, according to the complaint. He has not entered a plea; court records show his attorney filed a motion to dismiss that a judge denied. Sierra is scheduled to appear in court on Dec. 23. His attorney did not respond to requests for comment cited by PEOPLE.
This case remains under active investigation, and the allegations described in the complaint have not been proven in court.
