An 18-year-old Jefferson Park man was charged with fatally shooting his 17-year-old brother in their Jefferson Park home last week, prosecutors said Monday.

Brad Nicholson appeared at the Leighton Criminal Court Building after being charged with first-degree murder in the shooting of his brother, Ryan Nicholson, as their parents were in a nearby room, prosecutors said.

Nicholson was ordered held in lieu of $750,000 bail by Judge Donald Panarese Jr.

According to prosecutors and police, the brothers were in their home in the 5100 block of North Austin Avenue about 3 p.m. Friday.

Brad Nicholson got into an argument with their parents in the family's living room, prosecutors said. Then, the brothers began arguing, and their argument continued as the brothers went into the bedroom that they shared, prosecutors said.

The older brother had a loaded .45-caliber handgun in the room, which he pointed at his younger brother. The younger brother held his hand up in a defensive manner to cover his head as the older brother fired one shot, prosecutors said.

The parents heard shouting and a single, "loud sound" coming from the brothers' room. They then heard the older brother screaming.

Prosecutors said after the shooting, the older brother hid the gun, but it was later found by police.

The victim was taken to Advocate Lutheran General Hospital in Park Ridge, where he was pronounced dead at 3:21 a.m. Prosecutors said the boy suffered a wound in his hand as he attempted to block the shot as well as a single gunshot wound to his brain.