A 19-year-old wanted in the robbery tied to the killing of a Penn State student is now being sought in connection with another violent Philadelphia crime after an off-duty police officer exchanged gunfire with suspected car thieves.Khadfi Fleming is a person of interest in the Monday aggravated assault of the off-duty officer, according to the U.S. Marshals Service, which is offering an immediate cash reward for information leading to his whereabouts.The confrontation unfolded early Monday after thieves allegedly targeted the officer's Dodge Charger, Fox 29 Philadelphia reported.OFF-DUTY TROOPER AND ARMED CITIZEN HAILED AS HEROES AFTER RETURNING FIRE ON IN-N-OUT GUNMANThe off-duty officer followed the suspects and confronted them, leading to an exchange of gunfire, according to the outlet. No one is believed to have been struck.The suspects escaped, and investigators later recovered the officer's Charger with a broken window and damage to its steering column, along with numerous 9mm shell casings, Fox 29 reported.Authorities say the suspects moved to another stolen car – a Lexus that was later found abandoned.The U.S. Marshals Service has since publicly identified Fleming as a person of interest in the aggravated assault.MARSHALS NAB TEEN WANTED FOR MURDER OF PENN STATE STUDENT 1,700 MILES FROM CRIME SCENE, 2ND SUSPECT IN CUSTODY"USMS Philly is offering an immediate cash reward for Khadfi Fleming, 19, wanted for robbery," the agency wrote on X, adding that Fleming is also a "person of interest" in the Monday attack on the off-duty officer.Fleming has not been charged in connection with the Monday incident.But authorities were already looking for the 19-year-old before the latest violence.Fleming is wanted on a robbery charge connected to the June killing of Billy Schmidt, a 22-year-old Penn State student who was shot while walking home from an NBA Finals watch party.MANHUNT UNDERWAY AFTER COLLEGE STUDENT FATALLY SHOT CHASING ROBBERS WHO ALLEGEDLY STOLE HIS PHONESchmidt was just blocks from his South Philadelphia home when he was fatally shot around 1:30 a.m. on June 6.Surveillance video captured the final moments before the shooting, with Schmidt heard asking for his stolen phone back before a gunshot rang out.His father, Bill Schmidt, previously described his son as someone who "cared about everybody and never hurt or bothered a soul."MANHUNT UNDERWAY FOR KANSAS CITY SHOOTING SPREE SUSPECT NEAR WORLD CUP VENUE; FBI OFFERING $25K REWARD"For him to get shot like that is a travesty," he told ABC7.The killing sparked a search for two 16-year-old murder suspects, including Fleming's younger brother.U.S. Marshals captured Azzubair Outen-Fleming in Colorado Springs, Colorado, about a month after Schmidt's death. Authorities said the teenager was found at a distant relative's home and initially tried to conceal his identity.Philadelphia Police Department Deputy Commissioner Frank Vanore said Outen-Fleming would face a murder charge, Fox 29 reported.NEW YORK STATE POLICE LAUNCH MANHUNT AFTER KILLING, HOUSE FIRE FOR 'ARMED AND DANGEROUS' SUSPECTThe second teen, Kaiseem Smith, surrendered to Philadelphia police.Schmidt was studying digital journalism and media at Penn State and was expected to graduate in December.Now, two months after his killing, authorities are seeking the elder Fleming as they investigate whether he was involved in the latest violent encounter.Anyone with information about Fleming's whereabouts is urged to contact the U.S. Marshals Service at 1-866-865-TIPS (8477).Fox News Digital has reached out to the Philadelphia Police Department and U.S. Marshals Service for additional information and comment.Fox News Digital's Louis Casiano and Adam Sabes contributed to this report.