Fort Hood , Texas -LRB- CNN -RRB- -- Thirteen flag-draped coffins left Fort Hood on Friday as authorities searched for a motive in the massacre that left more than 50 casualties at the largest U.S. military base . Thursday 's mass shooting killed 12 soldiers and one civilian and wounded 38 people at the Fort Hood Army Post in Texas . The suspect in the shooting , Maj. Nidal Malik Hasan , a licensed Army psychiatrist , was among the two dozen who remained hospitalized Friday night . Hasan was transported to Brooke Army Medical Center in San Antonio , Texas , and was in critical condition but stable , a spokesman said . Investigators were waiting to speak to the comatose Hasan , who is under heavy guard , said Col. John Rossi , the post 's deputy commander . The bodies of the 13 personnel who died were transported through a `` ramp ceremony '' to Dover Air Force Base in Delaware for a dignified transfer , he said . It was a `` truly moving ceremony . '' FBI agents helping investigate the shootings searched Hasan 's apartment on Friday while investigators sifted through the crime scene , Fort Hood 's military processing center , where soldiers report before they go to war . Are you there ? Share your stories , photos and videos Hasan , who worked at a hospital on the base , is accused of using two handguns in the shooting . Two law enforcement sources told CNN that one of the weapons used is an FN 5.7-millimeter pistol , a semiautomatic purchased legally at Guns Galore , a Killeen gun shop . Details on the other gun , identified only as a type of revolver , were not immediately available . Rossi told reporters late Friday that both guns were privately owned and never registered at the post . Earlier , officials said investigators were looking into whether some soldiers may have been shot accidentally by others trying to shoot the gunman . However , Rossi said , `` All indications are that this is not a friendly fire incident . And , of course , that will be validated when the investigation is complete . '' Rossi attributed the high casualty rate to the `` more than 100 rounds '' fired by the gunman and the relatively small size of the room , among other factors . Fort Hood Police Sgt. Kimberly Munley , who has been credited with shooting Hasan and ending the massacre , was among the wounded . She was in stable condition Friday night , according to her family and military officials . Munley 's partner , Senior Sgt. Mark Todd , was also lauded for `` engaging '' the shooter , Rossi said . Todd , in an interview Friday night with CNN 's Anderson Cooper , described the intense scene as both officers fired shots at the accused gunman . `` He looked like he was calm . He was just pointing a finger at me , '' Todd said . `` The weapon ... I just know I saw the weapon and that 's when we returned fire . '' Todd , a retired member of the military police , offered his condolences to the families of the victims . `` I wish we could 've gotten there sooner and helped out a lot sooner -- but we got there as soon as we possibly could . '' Texas Gov. Rick Perry was scheduled to visit hospitalized victims of the shooting Saturday . As the Fort Hood community grieved its numerous losses , holding a candlelight vigil and setting up support lines , some details about the alleged gunman emerged . Relatives say Hasan , a U.S.-born citizen of Palestinian descent , was a `` calm '' individual who had been taunted after the terrorist attacks of September 11 , 2001 . Others described him as a vocal opponent to the war on terror whose rhetoric concerned colleagues . Fort Hood 's commanding general said witnesses have reported that the gunman yelled `` Allahu Akbar , '' Arabic for `` God is great , '' during the rampage . However , Lt. Gen. Robert Cone said investigators had not confirmed that . Hasan 's neighbors at his Killeen , Texas , apartment complex said he cleaned out his place just hours before the rampage and gave copies of the Quran to several residents . President Obama , in remarks Friday morning , cautioned against `` jumping to conclusions '' about what had triggered `` one of the worst mass shootings ever to take place on an American military base . '' He ordered that flags at the White House and other federal buildings be flown at half staff until Veterans Day , Wednesday of next week . `` This is a modest tribute to those who lost their lives , even as many were preparing to risk their lives for their country , '' the president said . `` It 's also a recognition of the men and women who put their lives on the line every day to protect our safety and uphold our values . We honor their service , we stand in awe of their sacrifice , and we pray for the safety of those who fight and for the families of those who have fallen . '' Obama said he met with FBI Director Robert Mueller and representatives of other relevant agencies to discuss the investigation . He promised his administration will provide updates . The central question investigators want to answer : Why would a member of the military who had been trusted with helping others achieve a healthier mental state allegedly shoot his comrades ? `` He took care of soldiers with behavioral health problems and also evaluated people who had disability evaluations , '' Braverman told reporters Friday morning . Asked whether Hasan , 39 , had seemed adequately prepared for his job , Braverman responded , `` We had no indication otherwise . '' According to the American Psychiatric Association , Hasan co-chaired a panel at the group 's May convention titled `` Medical Issues for Psychiatrists in Disasters . '' Military records show Hasan received his appointment to the Army as a first lieutenant in June 1997 after graduating from Virginia Tech in Blacksburg , Virginia , with a degree in biochemistry . Six years later , he graduated from the Uniformed Services University of the Health Sciences ' F. Edward Hebert School Of Medicine in Bethesda , Maryland , and was first an intern , then a resident and finally a fellow at Walter Reed Army Medical Center . He was promoted to major in May . Army Lt. Col. Wayne Hall said Hasan was to deploy to Afghanistan to work with a unit already there as part of behavioral health support . It was n't clear when Hasan was scheduled to go overseas for what would have been his first deployment . Since 2001 , Hasan had been telling his family that he wanted to get out of the military but was unsuccessful , said a spokeswoman for his cousin , Nader Hasan . She added that he told his family he had been taunted after the terrorist attacks of September 11 , 2001 . Nader Hasan issued a statement late Thursday on behalf of relatives , saying they were shocked by the shootings . Another family statement on Friday said , `` We are mortified with what has unfolded and there is no justification , whatsoever , for what happened . We are all asking why this happened -- and the answer is that we simply do not know . `` We can not explain , nor do we excuse what happened yesterday . Yesterday 's violence in no way reflects the feelings , beliefs , or principles of our family , '' the statement continued , adding that the family is cooperating with authorities . CNN 's Ted Rowlands and Michael Cary contributed to this report .