DALLAS (AP) — A Colorado congressman wants Secretary of Defense Robert Gates to provide answers on how a Texas man apparently tricked the Army into allowing him to enter the reserves as a noncommissioned officer.

Mike Coffman, a member of the House Armed Services Committee, delivered a letter to Gates' office on Monday asking him to address issues raised by an Associated Press story last Friday detailing the case of Jesse Bernard Johnston III.

The AP reported that Johnston, 26, was given the rank of sergeant when he enlisted in the reserves in February despite no military experience other spending six weeks in a 12-week Marine officer candidate course while he was in college in 2004. Because Johnston didn't complete the course, he never became a Marine.

The Army has refused to comment, citing an ongoing investigation.

Coffman, a Republican who served with the Marines in Iraq and the first Gulf War, wrote that he wants to know whether the Johnston case is an isolated incident or indicative of "a larger systematic failure" in vetting enlistees.

Coffman wrote that his office has obtained a copy of a phony Marine discharge document portraying Johnston as a veteran of campaigns in both Iraq and Afghanistan. He said the document, known in the military as a DD-214, may have been used by Johnston when he joined the Army Reserve.

"The fact that the Department of the Army does not immediately verify that someone has or has not previously served is both stunning and frightening," he wrote.

If someone without prior military experience could convince the Army to enlist him as a sergeant based on phony paperwork, it raises the possibility of a terrorist doing the same thing, Coffman said in his letter.

A Pentagon spokeswoman said a response will be provided to Coffman "as appropriate."

Johnston joined the Army's Corps Support Airplane Company based at the Fort Worth Naval Air Station. Although he never went overseas, members of his unit have been deployed to Iraq as part of an aviation battalion set up to destroy improvised explosive devices.

Since March, Johnston has been stationed at Fort Rucker in Alabama, the primary training base for Army aviation. He did not respond to phone and e-mail messages from the AP. A base spokeswoman has said she cannot comment on Johnston's status because of the ongoing investigation.

Johnston's ex-wife, also an Army reservist, has stated in an affidavit that Johnston obtained his rank in the reserves by falsifying documents that made it appear that he'd served in the Marines. Melanie Rolfing's sworn statement was filed in Fort Worth family court as part of a petition in which she sought to have her two-year-old marriage to Johnston annulled on grounds of fraud.

In the affidavit, Rolfing said Johnston led her to believe he'd served as a Marine in Iraq and Afghanistan and earned a Bronze Star and two Purple Hearts. She also said he would attend military functions in a Marine dress uniform that included the medals.

A judge issued a decree granting the annulment on May 4 when Johnston declined to contest it.