American soldiers can find ways to get their hands on alcohol in Afghanistan, despite a ban by the U.S. military, according to the Associated Press. This issue is in the spotlight now that investigators are looking into whether alcohol played a role when a U.S. soldier allegedly killed 16 Afghans earlier this month.

AP reports that U.S. investigators have determined the suspect was drinking before leaving the base the night of the attack.

The article notes that in stress-filled war zones, U.S. officers sometimes turn a blind eye to drinking, or even drink themselves, despite the ban on alcohol in military zones in Afghanistan and Iraq.

Soldiers from many other NATO countries are allowed to drink alcohol in Afghanistan, leading to some “alcohol spillover” to American troops on bases that house soldiers from various countries. In both Iraq and Afghanistan, most foreign contractors that deal with the U.S. military are not covered by the ban, and bring in their own alcohol. Some American soldiers receive alcohol hidden in other types of bottles that are sent by family and friends.

Soldiers who violate the U.S. military’s General Order No. 1 banning “possessing, consuming, introducing, purchasing, selling, transferring, or manufacturing any alcoholic beverage” in Iraq and Afghanistan can face discharge or criminal charges.

The U.S. Army recently announced it has decided to postpone expansion of its confidential alcohol treatment program for almost three years, citing a high dropout rate in its pilot phase. The Confidential Alcohol Treatment and Education Project is aimed at helping soldiers who abuse alcohol, before more serious substance abuse problems develop that could harmfully impact their finances, health, relationships and military career. The Army introduced the program in 2009 at three Army installations, and expanded it to six posts.