22-year-old in custody after mass shooting in Chicago during US independence day parade

The Chicago Police arrested 22-year-old Robert Crimo, who was armed with a high-powered rifle, in connection with a mass shooting that left six dead at a US independence day parade in Chicago.

The gunman on a rooftop opened fire, killing at least six people, wounding at least 30 and sending hundreds of marchers, parents with strollers and children on bicycles fleeing in terror. 

The suspect remained on the loose hours after as authorities scoured the area and the police surrounded a home listed as his possible address. 

The shooter opened fire around 10.15am CST, when the parade was about three-quarters through.

The motivation behind the incident is not immediately known.

US President Joe Biden on Monday said he and first lady Jill Biden were shocked by the senseless gun violence that has yet again brought grief to an American community on the independence day. 

At a time when the gun control debate in the US is at its peak, Biden had signed the widest-ranging gun violence bill passed by Congress in decades, a compromise that showed at once both progress on a long-intractable issue and the deep-seated partisan divide that persists.

More than 100 law enforcement officers were called to the parade scene or dispatched to find the suspected shooter.