Five years ago, my Afghan interpreter Janis Shinwari saved my life in a firefight against the Taliban. Ever since then, I've been trying to save his as the Taliban placed him on a kill list for his service to the US military.

Afghan and Iraqi interpreters are promised that if they give the United States military one year of "faithful and valuable service", they and their immediate families will receive Special Immigrant Visas to come to the United States. Janis has served our military for the past nine years. He has more than earned his place in America, so you can imagine our joy when after years of pleading with the State Department, the US embassy in Kabul issued him and his family US visas two weeks ago.

But this past Saturday, everything came crashing down. Janis called me at 2am in a panic. After giving him and his family their salvation, the State Department revoked it only two weeks later without any explanation.

I spent the next few days calling the US embassy in Kabul and State Department to no avail. After total silence, they finally told me that his visa was revoked for reasons they could not legally address. I investigated further and had my worst suspicions confirmed: in the two weeks since the State Department issued his visa, an anonymous "informant" contacted the US government and claimed all sorts of things about Janis. The informant's bogus claims eventually reached an analyst at the National Counter Terrorism Center (NCTC) in Washington DC who promptly put a security hold on Janis' visa, prompting the State Department to revoke it all together.

It's fairly common for the Taliban to read the US news. I can't help but think that they learned of our successful efforts to secure Janis his visa via the extensive coverage our efforts generated. They used to call our base in Afghanistan and claim all sorts of lies about our interpreters in an attempt to get us to fire them. The Taliban are almost certainly the source of the anonymous tip and now they have more time to hunt him and his family down and kill them.

If NCTC and the State Department were to go and check the validity of the source of whatever information prompted this revocation, I am certain it will turn up as not credible at all. The US government took years to review his information and after all that time they felt that he was good to go for a visa. And yet, suddenly, in the last two weeks, a magic piece of information that causes a revocation of his visa has just now come to light? I don't buy it. This development does not pass the logical plausibility test. If he was a bad guy, he would have killed me in the firefight and not two Taliban fighters.

After the State Department issued him his visas, he did what anyone in his situation would do – what I would do too – he sold his house, his possessions, and quit his job because he was told he was on his way to his new life in America. Now, he literally has nothing but the promise our nation made to bring him and his family to the US for his near decade of faithful, honorable, and heroic service to the US military. Apparently, the US government feels its perfectly routine and justified to break that promise.

Since his case attracted a large amount of US and international media attention, I fear it has only further raised his profile and his target for Taliban attacks. Any delay in his travel to the US raises the prospects of Taliban reprisal against him and his family. By revoking his visa, the US is literally endangering his life.

I fear at this point we can only save Janis by shaming the US government into doing the right thing.

I will do whatever I have to to save his life. The United States military doesn't leave a solider behind. Janis is a member of my unit – a brother in arms – still trapped in Afghanistan. I will not leave him behind.