There have been calls for investigators to look into what role, if any, the North's Deputy First Minister played on Bloody Sunday.
13 people were shot dead by the British Army in Derry in 1972.
The Saville Inquiry said it was likely Martin McGuinness was in the city and ''probably armed with a sub-machine gun.''
A murder investigation - involving up to 30 P-S-N-I staff - has now been launched by Police in the North.
Ulster Unionist MLA Tom Elliott believes Mr McGuinness has questions to answer: