The 37-year-old Michigan man who allegedly shot his 15-year-old son execution-style in a vacant lot was irate that the boy had had sex with his 3-year-old sister, The Associated Press reports.  

Highland Park Police filed first-degree murder charges against Jamar Pinkney Sr., Wednesday, saying he marched his son, Jamar Pinkney Jr., to an open lot, made him strip naked and shot him point-blank as the boy and the boy’s mother pleaded to spare his life.

Details: Detroit Man Executes Son

Corbett O'Meara, the attorney representing Pinkney Sr., said prosecutors should consider evidence of the father's state of mind over the sex abuse report, according to AP. "If something were to happen that would cause a reasonable person to lose control of himself, that is something the prosecution would have to take into account," O'Meara said outside the district court in Highland Park, a suburb of Detroit.

Judge Brigette Officer entered a not guilty plea for Pinkney, who's also charged with assault, and ordered him jailed without bond until a preliminary examination Dec. 1, AP reports.

This is something that's hard to deal with for all the parties concerned, including the police," Highland Park Police Chief Ted Caldwell said afterward. "Highland Park is a small city. These are people who have been members of the community for years." 

The boy's mother, Lazette Cherry, told The Detroit Free Press that her son told her he had improper sexual contact with the girl, AP reports. "I called and told his father. This isn't something you sweep under the rug," she said.

Cherry said the elder Pinkney arrived at the home with a gun, ordered his son to strip and marched him outside despite her protests.

He got on his knees and begged, ‘No, Daddy, no,’ and he pulled the trigger," Cherry said.