A soldier has told an inquest that he didn't realise they were shooting at British forces, and if he'd known he would have stopped immediately.
But Corporal Jonathan Dolton told the court that no messages about the location of Lance Corporal Michael Pritchard's watch post came through over the radio.
Michael Pritchard, 22 and from Eastbourne, was shot by a British sniper while he was on his first tour of duty in Afghanistan.
A British military policeman serving in Afghanistan was mistaken for an insurgent by fellow troops, because they didn't know his watch post was there.
Lance Corporal Michael Pritchard was killed by a British sniper when he was guarding a road in Helmand province in 2009.
A rifleman who fired warning shots on the night he died said he wasn't aware of a restricted firing line and radio communications between the bases was poor.
An inquest aims to answer key questions behind the death of a Sussex soldier, asking if he was shot by a British sniper. Twenty year old Lance Corporal Michael Pritchard was from Eastbourne but based at Aldershot. He was shot in Afghanistan in 2009.
Was a soldier from Sussex, shot dead in Afghanistan, killed by a British sniper? And if so, what went wrong? The key questions for an inquest which opened today into the death of Lance Corporal Michael Pritchard, from Eastbourne.
An inquest into the death of a military policeman killed in Afghanistan will investigate why he was shot by a British sniper. Charlotte Wilkins has the latest from the inquest.