That depends. Do you mean a case where Conan knew who the culprit was but they escaped in the middle of his deduction? I don't think so. There have been cases when a culprit did flee the scene of his crime but it's due to Conan/Police not knowing all the details of the case yet or any reason to suspect the culprit. They are eventually brought back to the scene of the crime or somewhere similar due to the plot and Conan gets them there.
There have also been cases where Conan has let a criminal leave thinking he got away with it, in order to trap him. And of course there's the common case of the culprit trying to run after the deduction only to have pain inflicted on them.




