I need to gain access to FB chat messages but don't know how can i do it professionally. Looking forward to some suggestions!

Try Cocospy, I can guarantee you that you will not find anything like that. By using this tool you would be able to gain access to all the messages that were being sent and received through Facebook Messenger easily. You can read a lot more about the tool from the Cocospy blog now. This software will start working within a couple of minutes and will send you a comprehensive repot about the things that were done through that account. Apart from current messages, you can gain access to the previous chats including names and contact numbers. This tool is reliable when it comes to privacy matters.