ST. JOSEPH, Mich. (AP) — A soldier at home in Michigan during the holidays was ambushed and killed by another soldier on New Year's Eve in a plot that involved the victim's wife, authorities said Monday.

Kemia Hassel, 22, and Jeremy Cuellar, 24, were charged with murder in Berrien County in southwestern Michigan. They're active duty soldiers at Fort Stewart in Georgia and were having an extramarital affair, prosecutor Mike Sepic said.

Sgt. Tyrone Hassel III, who was also stationed at Fort Stewart, was killed in St. Joseph Township after bringing food to his wife from a family gathering. The 23-year-old was a native of the Benton Harbor area and had a 1-year-old son with Kemia.

"It was planned out. Basically my son was assassinated," Tyrone Hassel Jr. said.

Cuellar is accused of ambushing and shooting Hassel. He's in custody in Liberty County, Georgia, and will be extradited to Michigan. It wasn't known if Cuellar and Kemia Hassel have attorneys yet.

"The motive for the two to plot Sgt. Hassel's death may have been to continue their relationship and reap the Army's death benefit from his murder," Sepic said.

He said investigators received key information from Army investigators at Fort Stewart.

Hassel's father said he's stunned by the allegations and was deceived by his daughter-in-law. A funeral was held Saturday.

"I spent two weeks with this person, after she killed my son. ... I grieved for her more than I grieved for myself. Because I saw a woman that lost her husband," Tyrone Hassel told WSBT-TV .