Andrew Walker said on Friday he would ask the British director of public prosecutions to bring those responsible for the death of Terry Lloyd to justice.
He said: "Terry Lloyd died following a gunshot wound to the head. The evidence this bullet was fired by the Americans is overwhelming."
The coroner said Lloyd, a reporter for the ITN network; Lebanese interpreter Hussein Osman; and French cameraman Fred Nerac were killed outside Basra on March 22 2003.
The Pentagon said its own investigation into the incident concluded in May 2003 that "US forces followed the applicable rules of engagement".
"The Department of Defence has never deliberately targeted non-combatants, including journalists," the Pentagon said in a statement
In a crossfire
The veteran correspondent was first shot in the back in a crossfire between US and Iraqi forces and then shot in the head by US troops as he was taken away in a minibus for treatment.
"There is no doubt that the minibus presented no threat to the American forces. There is no doubt it was an unlawful act of fire upon the minibus," Walker said.
Since the start of the Iraq war in March 2003, 118 journalists and media assistants have been killed, according to Paris-based Reporters sans Frontieres.
Fifty-one have been abducted, of which five are currently being held hostage.
According to figures compiled by the New York-based Committee to Protect Journalists (CPJ), 2006 has been the deadliest year for the media in the conflict so far with 25 deaths, compared with 22 last year and 24 in 2004.