Johnny Smith spent almost 24 hours shackled in the back of a prison van — barely conscious and muttering incoherently — before he died there in 2011. A private company was hauling Mr. Smith, 48, to Florida from Kentucky to face a drug charge: possession of a single oxycodone pill.

A judge ruled that the company’s “carelessness and gross negligence” had caused the death of Mr. Smith, a disabled construction worker, and awarded his children nearly $650,000 in damages.

Such lawsuits are the only recourse that families like the Smiths have against private prisoner transport companies, which remain almost entirely unregulated despite the industry’s extensive history of passenger deaths and injuries. Federal agencies that are supposed to oversee the industry almost never act, and because the vans cross state and county lines, local officials can say they don’t have jurisdiction.

[Read our original investigation into the prisoner transport industry.]

To this day, the Smiths have not gotten a dollar of what they are owed by USG7, the company that transported their father. As they and others have tried to hold the company to account for mistreating prisoners, an investigation by The Marshall Project and The New York Times found, the brothers behind USG7 have failed to appear in court, started a new company under a different name and claimed that its documents had gone missing in a U-Haul truck.