Mention detailed facts of your case then only can we guide you
We recieved a notice of investigation , want to talk about that .
Don't worry in any circumstance you have to join investigation I will advise you that before joining the investigation please consult a competent lawyer of your area.
Notice of investigation ? Is it under sec 41a CrPC from police ?
Any FIR filed against you or police/court calling to record statement as witness.
If you have received a notice from the police for investigation, I would advise you to assist the police in such investigation.
You should also get in touch with some lawyer and show him the said notice.
Also state as to what's your role in the case?
please give details
From your facts it seems that you have received notice under 41 A crpc you can post your query here or can call through kaanoon for any kind of assistance.