The US defence department inspector general will report a range of missteps and inappropriate conduct as the military investigated the death on the battlefront in 2004 of army ranger Pat Tillman, who gave up a multi-million-dollar career to join the military after the 11 September attacks on the US.

The Tillman case caused an outcry in the US because the army told his relatives the soldier had died a hero's death fighting the Taliban. The truth came out only last year.

An official said the IG investigation, the fifth into Tillman's death, does not appear to have found signs of a cover-up. The official said it appeared that senior military leaders may not have worked hard enough to get the facts of what happened on that day in April 2004.

Many soldiers . . . those immediately around Tillman at the scene of the shooting, his immediate superiors and high-ranking officers at a command post nearby . . . knew within minutes or hours that his death was caused by friendly fire. The IG investigation has focused on how high up the chain of command that knowledge went.

Officers from the rank of colonel upward will be blamed in the report, according to one officer who has been informed of the findings.

The commander of Tillman's 75th Ranger Regiment was then-colonel James Nixon. Last year he was named director of operations at the Centre for Special Operations at MacDill Air Force Base in Florida, headquarters of the US Central Command, in charge of the Iraq and Afghanistan wars.

According to the officials, the report will recommend the army look at holding the nine officers accountable. The IG is expected to release the report tomorrow and to speak to Tillman's family about the investigation. AP