A Missouri man is behind bars after he allegedly shot his more accomplished brother in the back of the head after an argument “over a girl.”

Court records show 43-year-old Jacob Ackerman faces charges of second-degree murder and armed criminal action. Cops in Sugar Creek, a suburb of Kansas City, started investigating around 10 p.m. Saturday after the victim”s family noticed he had not moved in seven hours, a probable cause statement said. Using the Life360 app, the family tracked his last known location to the area of Highway M-291 and Highway 210, the affidavit says.

The family member then provided cops with a more precise location of the northeast corner of a nearby pond. Officers went to the area and spotted the victim’s body. He was lying on the bank of the pond with a gunshot wound to the back of the head.

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Relatives who called police told detectives they suspected Ackerman was responsible for his brother’s death. According to the probable cause statement, relatives of the victim also called the medical examiner’s office and spoke with an investigator, who in turn told detectives that “while on the phone with the relative an unknown individual could be heard in the background stating the incident was a ‘Cain and Abel’ situation.”

Ackerman’s relatives noted that his mental health had been declining recently and he had been “jealous of the victim for most of his life due to the victim being successful,” while Ackerman struggled. They also told detectives they saw the victim’s Mercedes in Ackerman’s driveway.

Cops arrested Ackerman at a McDonald’s in Kansas City early Sunday morning. After he was detained, a relative asked him why he killed his brother and he looked at her with a “blank stare on his face,” the affidavit said.

According to detectives, the victim took a selfie photo with him and Ackerman at the exact location where his body was located, cops said. Investigators also recovered surveillance video from a nearby gas station that showed Ackerman and his brother arrive in the victim’s Mercedes, according to the affidavit.

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After receiving his Miranda warnings, Ackerman initially claimed he had no idea about the whereabouts of his brother. When he was told the situation looks bad, he allegedly stated “if it looks bad then it’s bad.”

When detectives asked Ackerman if they could search his home, he allegedly told them “you are going to do what you are going to do.”

But Ackerman eventually confessed, police said.