It's been almost a decade since the City Security Act came into force in San Paro, and in that time the city hasn't been cleaned up, in fact it's gotten more dangerous with the constant war between the various Enforcer and Criminal organisations making simply walking the streets an extreme sport. In a drastic attempt to make the streets safer, a group of prominent San-Paroans have joined to create the Red Hill Institute of Technology. Their solution: develop a compound that reduces aggression and lobby the San Paro government to force mandatory injection, under the cover of an emergency flu inoculation.
Their masterstroke was to reach out to Lawrence Holland, a wealthy San Parian with a lot of contacts in high places, including Jane Derren. She didn't need to know the details, but once convinced that a potential epidemic was on its way, she was happy to steamroll the council into giving the exclusive and lucrative contract to her long time friend.
With the government on board, Red-hill's scheme was rolled out in Havalynd, San Paro's Financial District, though something was bound to go wrong eventually. Before the first cases are out of the depot in Memorial Park, a vial was smuggled out by a G-King's Chemist, and it becomes clear very quickly what the actual intent is. An expose was on SPiN within the hour.
The district understandably imploded immediately. The common citizens fled for other areas of the city before they fell to the same fate as their burned out cars, while the four main gangs in the city either fought in support or against RIOT's plan. The G-Kings and Prentiss Tigers, long seen as protectors of the city, rallied against this clear attempt to attack the people they protect, while the Praetorian's had already been paid by the city to protect the plan. The Bloodrose's, while ambivalent to the actual morality of the plan, have a financial incentive as a number of their members have family within the Red Hill Institute (also, a compliant populace is far easier to rob).