Cockroaches die fully if they have their heads cut. And even then you have to separate them out of the way (like the head and body away from each other) so you know for sure its dead-dead. My grandmother taught us that lol. Its probably one of the first things she taught me and my brother since we used to lived somewhere where it was also infested with bugs (poverty sadly).
But yah, cockroaches are resilient bunch
It is one way to do it. But cockroaches basically eat and drink anything so there is no shortage of sustenance for them. What i should add in my response is: when you manage to separate the head and body, completely crush each of the parts. Yes they are able to survive a few days without the head, ive seen the body moved even when the head was cut off, but if you crush it, it had no hope of surviving.
Gross, but if you do that, then yknow for sure its dead
I don't know if I should be glad she's alive,or scared that I now know, cockroaches can revive themselves