Ever since the identity of the primary suspect in the Afghan massacre was leaked to the public, rumors raising questions about his military service record, his mental stability and his personal life have been swirling.

The U.S. Army staff sergeant Robert Bales, 38, who is being held responsible for the mass murder of 16 Afghan civilians, including 9 children, 3 women and 4 men, was arrested in the early hours of Sunday morning shortly after the shooting spree, which has caused a major fallout between the U.S. and Afghan administrations. His identity was leaked for the first time after he was brought to a maximum security cell in Fort Leavenworth, Kansas, from a temporary military prison in Kuwait.

Bales, who was enlisted in the U.S. Army shortly after the 9/11 attack, has served three tours in Iraq, before being deployed in Afghanistan.

The father-of-two, however, was reluctant to serve his Afghan assignment, said Bales' lawyer John Henry Browne. He was told that he was not going to be redeployed, Browne was quoted as saying by CNN. The family was counting on him not being redeployed. I think it would be fair to say he and the family were not happy that he was going back.

According to U.S. officials, Bales had been facing marital problems since his return from Iraq and before he was sent to Afghanistan. Bales had reportedly been drinking alcohol with two of his fellow soldiers on the night of the shootings, which was a violation of military rules in combat zones.

When it all comes out, it will be a combination of stress, alcohol and domestic issues - he just snapped, a U.S. official told the New York Times. Though alcohol was found on the base in the area where the suspect lived, it has not yet been officially proven that Bales acted under the influence of alcohol. The results of the toxicology screening have not been returned, officials said.

Browne, however, denied the allegations of marital problems. His family was totally shocked, Browne was quoted as saying by The Telegraph. He has never said anything antagonistic about Muslims, he has never said anything about Middle Eastern individuals. He has in general been very mild-mannered, so they were shocked by this.

According to Browne, the day before the shooting, another soldier on the base had his leg blown off in front of the suspect. That affected the whole base, Browne said. Bales had also lost a  part of his foot during one of his tours in Iraq.

Bales, with no recorded history of behavioral problems, suffered a concussion in a car accident on 2010, senior U.S. defense officials told NBC News. His treatment was successful and he was deemed to be fine. He also underwent mental health screening necessary to become a sniper and passed in 2008. He had routine behavioral health screening after that and was cleared, the official said.

Bales could face death penalty if proven guilty of the charges under the U.S. military legal code. However, no military member has been executed since 1960, though six military members currently face murder charges.

Gary Solis, an expert on military justice system, told Fox News that an insanity defense is likely in the case. It's hard to say whether the case will even go to trial because in war crimes like this it's very possible that there will be ... an insanity defense, that he is unable to recognize the wrongfulness of his act because of a severe mental disease or injury, Solis said.