Despite the subsequent analyses conducted after the brothers were identified, the most accurate were those first offered by their uncle and Russia's intelligence agency.
Their uncle, Ruslan Tsarni, described both young men as "losers." Russian intelligence described the older brother, Tamerlan, as a suspected Islamist extremist.
The descriptions these two sources gave, appearing dissimilar, really are not.
Tamerlan Tsarnaev was 26 when he drew his last breath -- a result of police gunfire and younger brother Dzhokhar Tsarnaev running him over in a car while attempting to escape.
Other than a failed boxing career, there was nothing of note Tamerlan accomplished in his brief life. His inability to support himself, let alone a wife and child, was a major concern his future father-in-law had upon first learning his daughter, Katherine Russell, was engaged to Tsarnaev.
As an immigrant, Tsarnaev and his family took advantage of various entitlements totaling tens of thousands of dollars. While such funds theoretically were to help build a better life, the financial gravy train apparently deadened Tsarnaev's drive to work hard to do so.
Despite this, he was able to purchase a car, a gun, explosive material and pressure cookers. Whether the funds he used came from such entitlements or elsewhere remains to be determined.
Also telling about Tsarnaev was his willingness to build the explosive devices inside his own apartment, where his baby daughter was close by. The "stay-at-home" dad apparently lacked any sense of responsibility to protect his child from danger.
Lacking such sense makes it easier to understand his lack of compassion for all human life -- although, as a Muslim, unbelievers didn't qualify.
Questions arise as to whether his wife Katherine Russell had any knowledge about the bombing plot. Dzhokhar Tsarnaev says no.
As a convert to Islam accepting a subservient role to her Muslim husband, Russell may well have learned not to make inquiries of Tamerlan.
A friend reported her to be an "all-American girl who was brainwashed by her super-religious husband." If so, one wonders how she now feels about a husband preferring death, with its supposed afterlife of 72 virgins, to life with her.
A pre-Boston bombing New York Police Department report assessed the type of person most susceptible to radicalization. It is one who is "unremarkable" and knows it. Consequently, neither his family nor friends think of him as being radical. He is someone who is malleable and thus easily influenced by a "spiritual sanctioner" or mentor showing him how to emerge from the shadows of mediocrity by taking action.
Usually, he is someone who has never received formal training in Islam. He easily identifies with radical Islam, which romanticizes the warrior role.
The brothers were known to read al-Qaida's Inspire magazine. One article described "exceptional" Chechen warriors who had performed "military miracles" against the Russians. Now indoctrinated in violent jihad, the brothers were inspired to emerge from the shadows of oblivion by delivering it to America again.
One can assume Tamerlan Tsarnaev's radicalization was complete three months prior to the bombing. Attending a mosque in Cambridge, Mass., he was forced to leave after interrupting a prayer service to criticize the imam for mentioning Martin Luther King, Jr. Tamerlan reportedly shouted, "You cannot mention this guy because he's not a Muslim!"
But there is another angle emerging that also may cast some light on why the brothers decided to bomb the Boston Marathon.
In September 2011, three young men were found killed -- their throats slashed -- in Waltham, Mass., just two towns over from Cambridge where the Tsarnaevs lived. One, Brandon Mess, was a friend and former roommate of Tamerlan Tsarnaev. The killings went unsolved.
Revisiting the case recently and awaiting DNA results, authorities have found forensic evidence and cellphone records linking the Tsarnaev brothers to the grisly crime.
Could it be, seeking to justify the murder of kafirs (infidels or unbelievers), they turned to the Koran -- a holy book promising eternal life for killing infidels?
Believing they had gotten away with murder perhaps the killers were imbued with a sense of infallibility. Left unaffected by personally killing three victims in such a gruesome manner, Tamerlan Tsarnaev undoubtedly would have had no problem committing the more detached crime of killing countless others with bombs.
It was only four months after these killings Tsarnaev returned to his ancestral home in southern Russia. With no specific purpose for the trip, was this simply an effort to avoid arrest should the murder investigation get around to focusing on him?
During his six months there, his father says he slept a great deal and studied the Koran. Russian officials monitored a phone call he had with his mother discussing jihad.
It may be Tamerlan Tsarnaev, after gaining confidence he wasn't a suspect in the murder investigation, decided it was safe to return to the United States. Was this the point in time he came to realize the Koran sanctioned his actions in targeting kafirs? An unsuccessful boxing career, an inability to support his family and a future murder arrest possibly lurking over his head, this loser had little left to lose.
It is a lack of self-worth that leaves one susceptible to radicalization, whether at home or abroad. Radical spiritual sanctioners sense this weakness and pounce on it, severing one's reason and independent thinking process. Whether this is what happened to Tamerlan Tsarnaev or whether he simply was a loser who became his own spiritual sanctioner remains to be seen.
Some people believe there is a little bit of good in everyone's life -- one need only look for it. If one looks for it in Tamerlan Tsarnaev's life, it came in his last dying moments, serving as a speed bump for his brother's getaway vehicle.
(Lt. Col. James G. Zumwalt, a retired Marine infantry officer, served in the Vietnam war, the U.S. invasion of Panama and the first Gulf War. He is the author of "Bare Feet, Iron Will--Stories from the Other Side of Vietnam's Battlefields," "Living the Juche Lie: North Korea's Kim Dynasty" and "Doomsday: Iran--The Clock is Ticking." He frequently writes on foreign policy and defense issues.)
(United Press International's "Outside View" commentaries are written by outside contributors who specialize in a variety of important issues. The views expressed do not necessarily reflect those of United Press International. In the interests of creating an open forum, original submissions are invited.)