If you could reasonably foresee that the thing was going to be used in that way, yes, you bear responsibility. It's not like you just happened to make something

If you could reasonably foresee that the thing was going to be used in that way, yes, you bear responsibility. It's not like you just happened to make something that just happened to be used for crime in addition to the more reasonable uses you expected it to be used for instead. Oh, granted, other people are responsible too - perhaps even more responsible than you. However, responsibility isn't an exclusive property, two or more people can be jointly responsible.