Veteran Congress party leader ND Tiwari today submitted his blood sample at his residence in Dehradun after the Supreme Court had earlier ordered that the police may use force if necessary to get the sample. Rohit Shekhar, and his mother were present at Tiwari's residence during the entire dicourse. Earlier today, the Uttarakhand Police stepped up security after a special team arrived at Tiwari's residence to collect blood samples for a DNA test in the alleged paternal lawsuit case