iStock/Thinkstock(PHILADELPHIA) — Philadelphia police arrested a 12-year-old boy after spotting him with an AR-15 rifle in hand on Saturday evening.Officer Krzysztof Wrzesinski arrested the teen and his 19-year-old brother in Northeast Philadelphia. The 19-year-old was in possession of a handgun, police said.Police said the brothers were on a public sidewalk at the time of the arrest. Someone placed a call from near the 2200 block of Kennedy Street, alerting officers to the 12-year-old, police said. Multiple weapons were recovered by police.The Philadelphia Police Department on Monday posted a photo on Twitter of Wrzesinski holding the confiscated rifle with the caption, “Parents: make sure your weapons are secured!”The department told ABC News it had no further comment regarding the arrests and an investigation was ongoing.Charges brought against the 12-year-old include assault, unlawful possession of a firearm by a minor and recklessly endangering another person.His older brother was charged with terroristic threats, criminal conspiracy, corruption of a minor and reckless endangerment of another person, and related offenses.Copyright © 2018, ABC Radio. All rights reserved.