Congressman Raúl Grijalva, and a group of his U.S. House Democratic colleagues, are asking President Obama to green light an independent investigation into the bombing of the Doctors Without Borders hospital in Kunduz, Afghanistan. 

In the letter, the group says they are "deeply disturbed" by the events, and that, under international law, hospitals in so-called conflict zones are protected places. "An independent investigation will help ensure future military engagements keep humanitarian heroes, like the MSF staff, safe," the letter says. They suggest collaborating with the United Nations in the investigation. 

In the beginning of October, U.S. airstrikes blew up part of the hospital, killing 12 staffers, 10 patients, and injuring nearly 40 others. 

From a CNN article:

As the United States said it was investigating what struck the hospital during the night, the charity expressed shock and demanded answers, stressing that all combatants had been told long ago where the hospital was.

"(The bombing) constitutes a grave violation of international humanitarian law," Doctors Without Borders, known internationally as Medecins Sans Frontieres, or MSF, said.

The bombardments continued even after U.S. and Afghan military officials were notified the hospital was being attacked, the charity said.

The circumstances weren't immediately clear, but the U.S. military was conducting an airstrike in Kunduz at the time the hospital was hit, U.S. Army Col. Brian Tibus said.

The military is investigating whether a U.S. AC-130 gunship — which was in the area firing on Taliban positions to defend U.S. special operations troops there — is responsible, a U.S. military official said on condition of anonymity.

The White House released a statement from President Barack Obama offering condolences to the charity from the American people.

"The Department of Defense has launched a full investigation, and we will await the results of that inquiry before making a definitive judgment as to the circumstances of this tragedy," the President said. "I ... expect a full accounting of the facts and circumstances."

“The American people and the international community deserve nothing less than full accountability and a thorough investigation into this tragedy,” Grijalva says in a statement to the media. “We must get to the full and unbiased truth about how our most lethal weapons of war were ever trained at a civilian target. Twenty-two people died as a result, and we cannot allow a similar tragedy to happen ever again.”

Read the whole letter:

We write to request a full and independent investigation to determine what led to the bombing of a Doctors Without Borders (MSF) hospital in Afghanistan. We appreciate your willingness to reach out directly to MSF to apologize and your call for a Pentagon investigation. We believe a civilian-led independent investigation is also necessary to ensure an impartial assessment and confidence in the findings of the investigation.

We are deeply disturbed by the news that U.S. airstrikes in Afghanistan destroyed the MSF trauma hospital in Kunduz, killing 12 humanitarian aid workers and 10 of their patients lying in their beds, including three children. The repeated airstrikes on the hospital also injured 37 civilians, including 19 MSF staff members.

Cooperating with a thorough investigation conducted by the United Nations or other independent body would send an important message to the world that the United States is unequivocally committed to the transparency and accountability required to ensure such a catastrophic event does not happen again.

Under international law, hospitals in conflict zones are protected spaces. An independent investigation will help ensure future military engagements keep humanitarian heroes, like the MSF staff, safe.

Your leadership and statements by our top military officials communicates the sentiment of many who are saddened by this tragedy: deep regret and a desire to ensure it never happens again. We look forward to working with you to ensure that the United States prioritizes protection of civilians in its conduct of military operations around the world.