Add a printf statement that prints something useful, e.g.
printf("Please enter a number: ");
char buf[32];
int n=atoi(buf);
printf("DEBUG: you entered %d\n",n);
So you can check the conversion was done properly and the program will continue with the expected value of n.
Applying that to your program then, you might want to print the contents of the murder object immediately after it was brought back from the file.