I am no proper follower of laws regarding money laundering, but if they won't go after the Tornado Cash (meaning the sanctions were dropped) then the devs might as well at some point see freedom. Arresting developers for just developing a software was already looking bad because it's not them that laundered the money or asked the Lazarus Group to use the platform.
They've made a case against Roman Storm saying he didn't stop money laundering after he knew. There's many ppl & companies who've donated to pay his legal bill because they believe he shouldn't have been arrested so until a judge says he's free he'll fight in court.
Unless there is proof from evidence like Roman's communications, I don't see how can they prove that he knew in advance that people were going to use Tornado Cash to launder money. While laundering is obviously a risk with any privacy protocol, that doesn't mean that its creation was intended for that.
I (sarcastically) wonder if any bank executives have been under this much scrutiny for laundering, since banks (arguably) have much worse laundering statistics/affiliation with criminal activity are much higher than that of what all of the crypto ecosystem have involvement with.
It wasn't intended for money launder but they've got email evidences saying he's guilty because he didn't stop money laundering after he knew it was happening. He's got to clear his name in court or he'll get years in prison.