Janesville police are investigating an armed robbery on the city’s south side. Police were called to the Golden Oil BP gas station at 1840 Beloit Avenue just after 5:00 a.m. Friday. Officers say a suspect entered the business, displayed a firearm, and demanded money from the register. The suspect didn’t get anything and initially fled on foot. Witnesses observed the suspect get into a White Chevrolet Avalanche with grey trim. Police say a short time later the suspect vehicle was spotted in Beloit and a short vehicle pursuit followed. The suspect crashed near the intersection of Rockport Road and South Walnut Street before being taken into custody.