After months of preliminary research, the Pentagon's Inspector General is launching a full-scale investigation into how U.S. troops and commanders handled repeated allegations that Afghan men, particularly Afghan military and police leaders, had sexually abused children boys

The IG's "research project" that began in October has revealed sufficient information to warrant conducting a "full assessment," into the matter, according to a Feb. 19 letter to top Defense Department officials from Kenneth Moorefield, the deputy inspector general for special plans and operations.

A number of American troops who deployed to Afghanistan have said they saw signs of widespread sexual abuse and believed there was a policy, even if unofficial, encouraging them to ignore the crime rather than create tension between Americans and their Afghans partners.

The sexual abuse of boys is widespread in Afghanistan, often referred to as "Bacha Bazi" — literally, "boy play." Several troops have said they were punished or disciplined for intervening or taking action against Afghans whom they believed were sexually assaulting children, in some cases on joint military installations.

Allegations of child abuse by U.S. allies and possibly on joint U.S. military facilities "has raised serious questions about international, U.S., and Department of Defense law or policy," according to the IG's letter. The investigation According to the letter, the IG's probe will focus on several questions, including:

• Is there or was there any Defense Department guidance, informal or otherwise, to discourage reporting by military affiliated personnel?

• Are U.S. military personnel authorized to use force to stop instances where they witness child sexual abuse by Afghan military personnel on bases in Afghanistan?

• When military leaders received reports of alleged or suspected abuse from troops under their chain of command, how did they respond?

• What laws, regulations or international treaties exist that might impact the U.S. military's policy toward allegations of child sexual abuse involving Afghan personnel?

• What training has been conducted or planned for U.S. military personnel for identifying and responding to alleged child sexual abuse, or the obligation to report suspected violations?

The IG probe comes at a time when the Army is preparing to make a final decision about a Green Beret who may be kicked out of the Army for beating an alleged child rapist in Afghanistan.

Sgt. First Class Charles Martland allegedly assaulted an Afghan police commander in 2011 after an Afghan boy's mother said the police commander beat her and raped her son. The case has garnered interest on Capitol Hill, namely from Congressman Duncan Hunter, a California Republican who also served as an officer in the Marine Corps.

Senate Armed Services Committee Chairman Sen. John McCain, R-Ariz., also has weighed in on the subject.

He said last year that lawmakers regard with "the utmost seriousness" such allegations involving Afghans.

"It is precisely because we're fighting for progress and fighting for our values that it's been so disturbing to read reports alleging that some of our coalition partners may be engaged in sexual abuse and other activities that contradict our values," McCain said.