Baltimore, a once prosperous city, lost many of its jobs along with its steel mills. In return, the city developed one of the biggest heroin problems in the country. For many of those that remain amid the poverty and abandoned homes, the “Heroin Hustle” is the way of life. One strip of Pennsylvania Avenue alone is estimated to take in $10 million a year from heroin sales. With the business booming, the heroin market is expanding outward to the suburbs, and the authorities are struggling to cope.