- Don't talk to the company at all. Don't explain anything. Don't say anything. The burden of proof is on them, not you. The more you talk, the more you are putting yourself at risk because the whole "Anything you say can be used against you" is really a thing. Even if you want to help them, don't.
- Being quiet is not an admission of guilt. Let them say whatever they want. Let them try to make you feel bad. You just don't respond with anything.
- Document everything you can in terms of your departure, timeline, what events occurred few weeks/days before your departure from the company. Write everything down. You may forget a few things later. Be specific.
- Stop talking to those other devs as well, at least about this issue. Better to not talk to them at all. Be very quiet.
Best case, the employer is just trying to find a scapegoat to blame for their own failures. They may move on if you don't fall for their blame game. Worst case, they are preparing legal action against you. In both cases, do not talk to them or anyone else about this issue except a lawyer who represents you.
EDIT: Btw, if anyone hasn't seen this video [0] at all, watch it. It is a great explanation by an attorney on why you should never talk to law enforcement without an attorney. Even if you are innocent and mean well.