If your investigation ends up in a court of law, be prepared to provide evidence that the tools you used did their job without corrupting the evidence. That can be a tough sell if you try to prove it by yourself. An easier course would be to use commercially available forensic tools that have been accepted by courts. If in doubt, ask your local law enforcement contact which tools are accepted in local courts. If you use tools a judge has seen before, you are likely to avoid a lot of wasted time.