Stealing from a murderer?

Illinois Supreme Court recently heard arguments over whether the state can take $11,000 saved over nearly 30 years in prison by a convicted murderer earning $2 a day (!) working behind bars. Because he saved the money rather than spending it in the commissary, it an enticing target for a state with (like everyone) huge deficits, especially when they’ve spent $455,000 to incarcerate him. Under Illinois law, prisoners are liable for the costs of their incarceration, but the state usually only goes after them when they have sufficient assets, above the $10,000 threshold. Also, the state already extracts 3% (like the state income tax) from prisoners to cover costs. Although I’m sympathetic to the budgetary problems and the costs of jail, this is an ex post facto punishment, essentially punishing him again for having saved rather than spending his earnings. He’s due to be released in 2028, and this seems to really disincentivize work and thrift.