Years of hard work, resistance from prosecutors and an uphill legal climb are to be expected when an attorney takes on a wrongful conviction case. But most attorneys don’t expect to be threatened by an incarcerated gang member.

That was just one of the hurdles Sidley Austin partner Paul Hemmersbaugh and his team encountered during seven years representing David Housler, serving life for a notorious quadruple murder in Tennessee in 1994. Most notably, Hemmersbaugh had to figure out how to prove Housler’s innocence, given that the then-19-year-old confessed to the crime. Another complication: A tornado had barreled though the local courthouse years earlier, destroying key documents in the case. Then, he said, there were prickly judges and prosecutors who feared an exoneration in the politically sensitive case.