The power in the Magistrate to order further investigation u/s 156(3) is an independent power, and does not affect the power of the investigating officer to further investigate the case even after submission of his report vide Section 173(8). Hence the Magistrate can order re-opening of the investigation even after the police submits the final report, vide State of Bihar and Another Vs. J.A.C. Saldanha and Others[1]
[1] State of Bihar and Another Vs. J.A.C. Saldanha and Others, AIR 1980 SC 326 : (1980) CriLJ 98 : (1980) 1 SCC 554 : (1980) SCC(Cri) 272 : (1980) 2 SCR 16