St. Louis, MO  (KTRS)  Two teenagers are in juvenile custody in connection with the murder of retired St. Louis Police Sergeant Ralph Harper.

Police say the suspects are a 15-year old male and  a 16-year old male. Their names are being withheld unless they are Certified as an Adult with warrants issued. A third teen, 17-year-old  Julian Mathews was arrested and charged with one count of 2nd degree tampering and one count of resisting arrest. Police say Matthews was not involved in Harper’s murder.

Investigators say Harper was parking his car Monday morning near Tower Grover Park when he was approached by an armed robber. Harper had his own gun and exchange gunfire with the suspect.

Harper worked for the police department for 33 years before retiring in 2007.