Fentanyl: The million dollar streets strewn with bodies contorted by the effects of the drug

Drug-related deaths surged by 41% in San Francisco in the first three months of this year - with an average of one person dying of an accidental overdose every 10 hours. The drug-ravaged Tenderloin district is worst affected.

Sky's Martha Kelner has witnessed people strewn on the doorstep of San Francisco's main government building, contorted by the effects of fentanyl, a painkiller 100 times more potent than morphine.