In connection with Insights to 116b, I asked what would be today. The answer of the one in question, said that if a person has no money, there is no reason to assume the thief will harm you, so you can't take any action against the thief. What would be the teshuva today? You only need to read the first 2 paragraphs below
"On Wednesday evening a Frum man was out in his jogging path when he was brutally assaulted. "I don´t think for a minute that you, when I´m talking to the perpetrators and those like you, care about other people, otherwise you wouldn´t do this,? he said. "First thing they did was pummelling my head with the gun and then my face, then punching me and kicking me. Repeatedly I kept saying ?let me go, I have nothing.´?"
"Neighbors in the North Miami Beach community are also concerned for their safety. "It seems like it is a big problem and it seems like this kind of stuff happens nearly every night. We feel so unsafe out there. We don´t even go to the canal or to the park anymore,? said a woman whose husband was also assaulted in that same path."
It could be that today's modern day armed bandit enjoys gratuitous violence and therefore he doesn't have the Chazakah of Tosfos (Bava Basra 7b, DH l'Fi) that he won't harm the victim if has no money, in which case he has the Din of a Rodef and he can be stopped with whatever measures are necessary.
Rav Chaim Ozer Grodzenski (Vol III, #72) says that a Safek Rodef cannot be killed (but presumably he can be immobilized by whatever means are necessary).
Kol Tuv,
Yonasan Sigler
This is not a Psak Halachah