NOGALES, Ariz. (AP) — A March 21 trial date was set Wednesday for an Arizona rancher accused of fatally shooting a migrant on his property near the U.S.-Mexico border last year.

George Alan Kelly rejected a plea deal offered by prosecutors Wednesday that would have reduced charges to one count of negligent homicide if he pleaded guilty, the Arizona Republic reported.

Kelly’s trial in Santa Cruz County Superior Court is expected to last three weeks, the newspaper said.

Kelly, 75, was arrested and charged with second-degree murder and aggravated assault in the Jan. 30, 2023, shooting of 48-year-old Gabriel Cuen-Buitimea of Nogales, Mexico.

Authorities said Kelly shot at a group of unarmed migrants who were walking through his nearly 170-acre cattle ranch in the Kino Springs area, and Cuen-Buitimea was among them.

According to prosecutors, Kelly recklessly fired an AK-47 rifle toward the migrants, who were about 100 yards away from him.

But Kelly’s lawyer said her client shot into the air above the migrants, and he feared for his and his wife’s safety and the property.

The other migrants weren’t injured and managed to escape back to Mexico.

Cuen-Buitimea also entered the U.S. illegally several times and was convicted and deported, most recently in 2016, court records show.

The shooting has stirred emotions as the national debate over border security heats up ahead of the 2024 presidential election.