A Texas man with no military experience managed to trick the US army into letting him enter a reserve unit as a noncommissioned officer earlier this year, putting an untrained soldier in a leadership position in a time of war.

The revelation comes just months after the army drew criticism for failing to raise the suspicious activities of Major Nidal Hasan, the army psychiatrist now charged with killing 13 and wounding dozens of others at a military base in Fort Hood.

The case, detailed in court records and other documents examined by the Associated Press, raises more questions about the army's ability to vet soldiers' backgrounds as it faces continued pressure from Congress over its screening and records system. While the soldier never deployed overseas, the case demonstrates how easily someone could pose as a member of the US military.

Jesse Bernard Johnston III, 26, joined the army reserve in February as a sergeant and was assigned to the Corps Support Airplane Company based at the Fort Worth naval air station. But he was not qualified to hold that rank, according to military records obtained by the AP. The records show that Johnston's only military experience was attending part of a 12-week Marine officer candidate course for college students in 2004.

Major Shawn Haney, spokeswoman for Marine Manpower and Reserve Affairs, said Johnston didn't complete the course's final six weeks. "He was never considered a Marine," she said.

The matter, currently under investigation by the army, means a soldier received a security clearance and was in position to lead troops in combat even though he had not gone through basic training or spent any time in the service. The Corps Support Airplane Company has been deployed in Iraq, providing pilots as well as intelligence and support personnel for an aviation battalion set up to destroy improvised explosive devices.

If it is proven that Johnston gained his army rank based on a phoney Marine record, it would be the first documented case of so-called "stolen valour" in which the military was duped during the enlistment process, according to watchdogs of such fraud.

Most cases involve attempts to get veterans' benefits or other forms of financial gain. Congress attempted to crack down on military impostors in 2005 by passing a law that made it a crime to claim false decorations or medals.

"This just raises some incredibly significant issues at a time when this country is involved in a global war on terror," said US Representative Mike Coffman, a Colorado Republican who served with the Marines in Iraq. "If this person was able to penetrate the military fraudulently, you have to ask the question: couldn't somebody who was out to do harm to our country do the same thing?"

Army officials, citing an ongoing investigation, declined to provide details of Johnston's enlistment or say whether he was suspected of providing false documents or using some other means to make himself out to be an ex-Marine.

Questions about Johnston were raised by an officer who grew concerned when Johnston couldn't satisfactorily explain how he got certain Marine medals and ribbons that he displayed. The officer, speaking on condition of anonymity because of the ongoing investigation, said he contacted Marine and army legal authorities and learned from the Marines that Johnston never served.

In a recent court proceeding, Johnston's former wife, also an army reservist, accused him of using falsified documents to make it appear he had served in the Marines. Melanie Rolfing, 24, made the claim in a sworn statement filed last month in Fort Worth family court when she had her two-year-old marriage annulled, alleging fraud. Johnston did not contest the annulment.

In her affidavit, Rolfing said she met Johnston in 2006 and that he joined her Army Reserve unit so they could fulfil their dream of becoming army aviators together. She said Johnston led her to believe he had served as a Marine in Iraq and Afghanistan and earned a Bronze Star and two Purple Hearts. He would even attend military functions wearing a Marine dress uniform, and people would come up to shake his hand and ask about his medals, she said.