IMPHAL, March 8: The proscribed outfit PREPAK has in a press statement declared as invalid and void the letter heads which were seized from one Bramhacharimayum Kiran Sharma alias Ingocha (37) son of (L) B Manglem Sharma on March 5 around 4:15pm from Palace Compound by a combined team of Imphal East district police commandos and the 16th Assam Rifles.