well in my opinion, the money was taken on behalf of Buta Singh, ultimately he was to do the things for that contractor.
genuineness of the notes not to be considered reason being the mens rea and actus reus involved in the case was confined to corruption.....however possession of fake notes may result into filing of another case.
I agree with Mr. Kiran Kumar Sir. There may be charge of Criminal conspiracy among Boota Singh and his son so with aid of Sec. 120B of IPC he may be prosecuted after fulfilling required legal necessities.