PHOENIX - Aaron Saucedo is a person of interest in the Serial Street Shooter case, but Friday's court appearance was for a different murder charge from back in 2015.

Saucedo, 23, was arrested for a shooting that happened near 7th Street and Missouri. He pleaded not guilty Friday.

The case is getting a lot of attention because investigators are questioning whether the suspect, Saucedo, is related to the serial street shootings. Those shootings left seven dead and several others injured.

Saucedo was put in handcuffs last month because police say he sold a handgun they believe was used in that 2015 murder. Police then used forensic evidence to find the gun used in the shooting was a Hi-Point handgun.

A records check also showed that Saucedo sold a Hi-Point handgun to a pawn shop just 16 days after the shooting. Court paperwork reveals he had a connection to the victim, but we don't know what.

Saucedo faces a first-degree murder charge for that 2015 murder.