Before issuing any notice U/S 148 the assessing officer must have reason to believe that any income chargeable to tax has escaped assessment. Reason to believe can not be a reason to suspect merely. There must be a direct nexus between the material coming to the notice of the assessing officer and the formation of the belief that there has been escapement of income of the assessee from assessment in a particular year. The material for formation of belief must be relevant and not vague. The assessing officer must record reasons in writing before issuing notice u/s 148. Mere a reason recorded that “there is a huge concealment of income’ or ‘For further investigation’ without any specific instance of entries or material relevant to the assessee will not constitute a valid reason as it is vague and general in nature.
Just write a letter mentioning that it was a mistake. There should be no much problem in justifying yourself in this case.