Staff Sgt. Robert Bales, the American soldier accused of slaughtering 17 Afghan civilians, stopped at his military base between killings, a U.S. official told ABC News.
The official says it was Bales' second departure from Camp Bellambay that led to a search party being organized to look for Bales after he was not found present for a muster organized to see if anyone was missing from the base.
Bales was detained after he returned on his own accord to the base after the attack on the second village. U.S. officials say there is aerial surveillance video taken by a security blimp located over the base that shows Bales in a prone position making his way back to the base after the second attack. His detention is not shown on the video.
The U.S. official confirmed that investigators believe that Bales returned to the base after the attack on the first village, which was first reported by The Associated Press, but does not believe that he was detected leaving the base the first time.
"We know he made two trips," said the U.S. official, who would not provide details as to how investigators know that Bales returned to the base in between the attacks, though he said there is no video showing Bales returning to the base the first time.
The official did not know Bales' motivation in returning to the base the first time.
An Afghan guard working from midnight to 2 a.m. on March 11 saw a U.S. soldier return to the base around 1:30 a.m., and guard working the following shift said he saw a U.S. soldier leave the base at 2:30 a.m., said members of the Afghan delegation investigating the killings, according to the AP.
Bales was officially charged Friday with 17 counts of murder, six counts of attempted murder and six counts of aggravated assault, military officials said.
The 38-year-old is accused of leaving his base in Kandahar, Afghanistan, in the middle of the night Sunday and walking to nearby villages where he broke into homes and opened fire on the families inside. Afterwards, he allegedly set some of the bodies on fire. Four women and nine children were killed, according to the criminal charges filed against Bales yesterday.
Just moments after the alleged attack, Bales called his wife from Afghanistan and told her "something terrible" had happened, the wife's lawyer told ABC News today. Bales had apparently surrendered to coalition forces and was able to speak with his wife for about three minutes before the phone call was cut off.
A high-powered civilian defense attorney for Bales, John Henry Browne, told ABC News Tuesday that Bales does not remember all of the night in question -- just the beginning and the end, but not the period during which the murders supposedly took place.
Browne said he doubts the military's version of events, said it's not supported by eyewitnesses or forensic evidence and said he had not seen any documents that suggest Bales confessed to the crime, contrary to earlier reports.
Since his arrest, ABC News has learned Bales had been accused of bilking more than $1 million from an elderly couple and was under scrutiny in a financial probe when he joined the military in 2001.
The AP reported that Bales had allegedly previously been involved in a 2008 incident in which a woman claimed Bales made inappropriate advances on her and then assaulted her boyfriend.
Browne has said Bales was not drunk the night of the alleged attack in Afghanistan, though military officials said alcohol was found close to his quarters.
Bales, who has a home in Washington State where his wife and children live, is now being held at Fort Leavenworth, Kansas, and though charges in his case were filed by U.S. Forces in Afghanistan, U.S. officials say his military court proceedings will be held in the United States.
The Associated Press contributed to this report.