AMMAN, Jordan (AP) — A military court is set rule Monday in the murder trial of a Jordanian soldier accused of gunning down three U.S. military trainers in a shooting spree at a Jordanian air base.

The high-profile case had caused some friction between military allies Jordan and the United States. Jordan initially suggested the U.S. troops triggered the shooting by disobeying gate procedures, a claim it later withdrew.

The defendant pleaded “not guilty,” saying he opened fire because he believed the base had come under attack.

If convicted, he faces life in prison. In Jordan, a life sentence can mean a 20-year term, with good behavior.

Relatives of the victims attended the month-long trial in Jordan’s capital. Some of the family members sharply criticized the legal proceedings and potential punishment as inadequate.