Arrest made in August shooting death of Chicago cop's son

Mugshot for Anthony Moore, 18, charged with murder of Chicago police officer's son. (Chicago Police Department)

The teenage son of a Chicago police officer was mistaken for a gang member when he was killed last summer, police said Friday in announcing an arrest in the case.

Arshell Dennis III was a college student in New York City at the time of his death Aug. 14. He was home visiting his sick mother.

Police charged gang member Anthony Moore, 18, of Chicago, with first degree murder.

Dennis was on his family's porch with two friends on Chicago's Southwest Side around midnight when police say Moore walked up and opened fire. One of the friends was shot in the arm.

Moore was with others, police said. They came up on Dennis after stealing cars.

Dennis was shot in the chest. He was pronounced dead at a hospital.

Police said Moore mistook Dennis for a gang rival. Chief of Detectives Melissa Staples said Dennis and his friends had no affiliation with any gang.

Detectives said they became aware of Moore’s involvement after he bragged about the killing to friends.

He has been arrested six times since turning 18 shortly after the killing.

“This is not his first go around with the criminal justice system,” Police Superintendent Eddie Johnson said.

Dennis' death was one of 91 homicides during the deadliest month in Chicago in two decades.

The teen was  a journalism major at St. John’s University in New York City, entering his junior year, Fox 32 reported.

In announcing the arrest, Chicago Police spokesman Anthony Guglielmi tweeted: “We promised we’d never stop & we didn’t. Murderer of Police Officer Arshell Dennis’ son from last year has been charged.”