Why not follow the money...
...in general, USA...
"As prison populations explode nationwide, more companies are using prisons for cheap and controlled labor to produce a range of private sector goods, from Microsoft equipment to aircraft components."
http://www.democracynow.org/1997/4/25/us_prison_labor_and_us_corporations
" ... "Due in part to Rockefeller-style laws [
incarceration over rehabilitation], the nations prison population exploded from 330,000 in 1973 to a peak of 2.3 million. That meant building hundreds of new state and federal prisons. By 2010, more than 490,000 people were working as prison guards."
Such growth naturally attracted the attention of those who saw this as a money-making proposition and thus emerged the private prison industry. In 1984, the Corrections Corporation of America (CCA) came into being and is now the largest private prison business with 2011 revenues of $1.7 billion, with the Geo Group being second with $1.6 billion. There are now about 130,000 people in private prisons....
"...The private contracting of prisoners for work fosters incentives to lock people up. Prisons depend on this income. Corporate stockholders who make money off prisoners' work lobby for longer sentences, in order to expand their workforce. The system feeds itself," says a study by the Progressive Labor Party, which accuses the prison industry of being "an imitation of Nazi Germany with respect to forced slave labor and concentration camps."
The prison industry complex is one of the fastest-growing industries in the United States and its investors are on Wall Street. "This multimillion-dollar industry has its own trade exhibitions, conventions, websites, and mail-order/Internet catalogs. It also has direct advertising campaigns, architecture companies, construction companies, investment houses on Wall Street, plumbing supply companies, food supply companies, armed security, and padded cells in a large variety of colors."
According to the Left Business Observer, the federal prison industry produces 100% of all military helmets, ammunition belts, bullet-proof vests, ID tags, shirts, pants, tents, bags, and canteens. Along with war supplies, prison workers supply 98% of the entire market for equipment assembly services; 93% of paints and paintbrushes; 92% of stove assembly; 46% of body armor; 36% of home appliances; 30% of headphones/microphones/speakers; and 21% of office furniture. Airplane parts, medical supplies, and much more: prisoners are even raising seeing-eye dogs for blind people."
http://freethoughtblogs.com/singham/2013/03/13/the-drug-war-and-the-us-prison-industry/
The italics in square brackets are mine, to aid understanding and refer to drug taking and supply.