Michigan jurors, after 11 hours of deliberations, found Jennifer Crumbley guilty of involuntary manslaughter on Tuesday for the gun rampage committed by her son, who carried out the state’s deadliest school shooting more than two years ago.

Ms. Crumbley, 45, was convicted on four counts of involuntary manslaughter, one for each of the four students who were shot to death by her son at Oxford High School on Nov. 30, 2021. The son, Ethan Crumbley, who was 15 at the time, used a pistol to kill Madisyn Baldwin, 17; Tate Myre, 16; Justin Shilling, 17; and Hana St. Juliana, 14. Seven other people were injured. The gun was a gift from his parents.

She faces a maximum penalty of 15 years in prison after being convicted of all four counts.

Ethan, who pleaded guilty to 24 charges including first-degree murder, was sentenced last year to life in prison without the possibility of parole. He did not testify in his mother’s trial. Ms. Crumbley’s husband, James Crumbley, 47, will be tried separately in March.

The trial became a lightning rod for issues of parental responsibility at a time of frequent cases of gun violence carried out by teenagers and children.

In the last few months, parents whose children carried out gun violence in other states have pleaded guilty to charges of reckless conduct or neglect, part of a push by some prosecutors to hold parents accountable when they are suspected of enabling deadly violence.

But the charges against Ms. Crumbley were even more serious, making her trial a significant test case for prosecutors.