SAN FRANCISCO (KRON) -- A 29-year-old man who San Francisco police said was riding a bicycle dangerously was arrested after officers located a stolen, loaded firearm in his possession, according to authorities. On Oct. 7 at around 7:30 a.m., San Francisco Police Department patrol officers in the area of Mission and Julia streets observed a man on a bicycle riding against traffic, running a stop sign and making unsafe lane changes. The officers attempted to stop the bicyclist, but their commands were ignored, SFPD said. Once police were able to stop and detain the suspect, identified as Guillermo Ybarra, 29, of Belmont, officers seized a loaded firearm. According to SFPD, the gun was stolen. A stolen, loaded firearm was seized during the arrest of Guillermo Ybarra, SFPD said. (Photo: San Francisco Police Department) Ybarra was transported to a hospital for medical evaluation before being booked into the San Francisco County Jail on charges of: Carry a concealed firearm Carry a concealed firearm on person Two counts of carrying a loaded firearm Having a controlled substance while armed Felon in possession of ammunition Possession of drug paraphernalia Resisting arrest Running a stop sign Possession of sedatives without prescription A vehicle shall only be driven only in direction designated Unsafe lane changes Along with the new arrest charges, Ybarra had five active and outstanding warrants out of San Mateo County, SFPD said.