Note that the JSON string you present in this post is different from the one presented in the OP and so does not match with choroba's code here. Is
    "del_info" : [ ... ]
or
    "deluser" : [ ... ]
correct? (Everything else seems the same.)

Update: Another link that might be helpful in dealing with the complex data structures that can be produced by JSON parsing is the Perl Data Structures Cookbook (or perldsc).