The big questions buzzing over Boston Bombers Tamerlan and Dzhokhar Tsarnaev have a single answer: It emerged in the 102 tense hours between the twin Boston Marathon bombings Monday, April 15 – which left three dead, 180 injured and a police officer killed at MIT - and Dzohkhar’s capture Friday, April 19 in Watertown.
The conclusion reached by DEBKAfile’s counterterrorism and intelligence sources is that the brothers were double agents, hired by US and Saudi intelligence to penetrate the Wahhabi jihadist networks which, helped by Saudi financial institutions, had spread across the restive Russian Caucasian.
Instead, the two former Chechens betrayed their mission and went secretly over to the radical Islamist networks.
By this tortuous path, the brothers earned the dubious distinction of being the first terrorist operatives to import al Qaeda terror to the United States through a winding route outside the Middle East – the Caucasus.
This broad region encompasses the autonomous or semi-autonomous Muslim republics of Dagestan, Ingushetia, Kabardino-Balkaria, Chechnya, North Ossetia and Karachyevo-Cherkesiya, most of which the West has never heard of.
Moscow however keeps these republics on a tight military and intelligence leash, constantly putting down violent resistance by the Wahhabist cells, which draw support from certain Saudi sources and funds from the Riyadh government for building Wahhabist mosques and schools to disseminate the state religion of Saudi Arabia.
The Saudis feared that their convoluted involvement in the Caucasus would come embarrassingly to light when a Saudi student was questioned about his involvement in the bombng attacks while in a Boston hospital with badly burned hands.
They were concerned to enough to send Saudi Foreign Minister Prince Saudi al-Faisal to Washington Wednesday, April 17, in the middle of the Boston Marathon bombing crisis, for a private conversation with President Barack Obama and his national security adviser Tom Donilon on how to handle the Saudi angle of the bombing attack.
That day too, official Saudi domestic media launched an extraordinary three-day campaign. National and religious figures stood up and maintained that authentic Saudi Wahhabism does not espouse any form of terrorism or suicide jihadism and the national Saudi religion had nothing to do with the violence in Boston.  “No matter what the nationality and religious of the perpetrators, they are terrorists and deviants who represent no one but themselves.”
Prince Saud was on a mission to clear the 30,000 Saudi students in America of suspicion of engaging in terrorism for their country or religion, a taint which still lingers twelve years after 9/11. He was concerned that exposure of the Tsarnaev brothers’ connections with Wahhabist groups in the Caucasus would revive the stigma.
The Tsarnaevs' recruitment by US intelligence as penetration agents against terrorist networks in southern Russia explains some otherwise baffling features of the event:
1.  An elite American college in Cambridge admitted younger brother Dzhokhar and granted him a $2,500 scholarship, without subjecting him to the exceptionally stiff standard conditions of admission. This may be explained by his older brother Tamerlan demanding this privilege for his kid brother in part payment for recruitment.
2.  When in 2011, a “foreign government” (Russian intelligence) asked the FBI to screen Tamerlan for suspected ties to Caucasian Wahhabist cells during a period in which they had begun pledging allegiance to al Qaeda, the agency, it was officially revealed, found nothing incriminating against him and let him go after a short interview.
He was not placed under surveillance. Neither was there any attempt to hide the fact that he paid a long visit to Russia last year and on his return began promoting radical Islam on social media.
Yet even after the Boston marathon bombings, when law enforcement agencies, heavily reinforced by federal and state personnel, desperately hunted the perpetrators, Tamerlan Tsarnaev was never mentioned as a possible suspect
3.  Friday, four days after the twin explosions at the marathon finishing line, the FBI released footage of Suspect No. 1 in a black hat and Suspect No. 2 in a white hat walking briskly away from the crime scene, and appealed to the public to help the authorities identify the pair.
We now know this was a charade. The authorities knew exactly who they were. Suddenly, during the police pursuit of their getaway car from the MIT campus on Friday, they were fully identified. The brother who was killed in the chase was named Tamerlan, aged 26, and the one who escaped, only to be hunted down Saturday night hiding in a boat, was 19-year old Dzhokhar.
Our intelligence sources say that we may never know more than we do today about the Boston terrorist outrage which shook America – and most strikingly, Washington - this week. We may not have the full story of when and how the Chechen brothers were recruited by US intelligence as penetration agents – any more than we have got to the bottom of tales of other American double agents who turned coat and bit their recruiters.
Here is just a short list of some of the Chechen brothers’ two-faced predecessors:
In the 1980s, an Egyptian called Ali Abdul Saoud Mohamed offered his services as a spy to the CIA residence in Cairo. He was hired, even though he was at the time the official interpreter of Ayman al-Zuwahiri, then Osama bin Laden’s senior lieutenant and currently his successor.
He accounted for this by posing as a defector. But then, he turned out to be feeding al Qaeda US military secrets. Later, he was charged with Al Qaeda’s 1998 bombings of US embassies in Nairobi and Dar es-Salaam.
On Dec. 30, 2009, the Jordanian physician Humam Khalil al-Balawi, having gained the trust of US intelligence in Afghanistan as an agent capable of penetrating al Qaeda’s top ranks, detonated a bomb at a prearranged rendezvous in Kost, killing the four top CIA agents in the country.
Then, there was the French Muslim Mohamed Merah. He was recruited by French intelligence to penetrate Islamist terror cells in at least eight countries, including the Caucasus. At the end of last year, he revealed his true spots in deadly attacks on a Jewish school in Toulouse and a group of French military commandoes.
The debate has begun over the interrogation of the captured Boston bomber Dzhokhar Tsarmayev when he is fit for questioning after surgery for two bullet wounds and loss of blood. The first was inflicted during the police chase in which his brother Tamerlan was killed.
An ordinary suspect would be read his rights (Miranda) and be permitted a lawyer. In his case, the “public safety exemption” option may be invoked, permitting him to be questioned without those rights, provided the interrogation is restricted to immediate public safety concerns. President Barack Obama is also entitled to rule him an “enemy combatant” and so refer him to a military tribunal and unrestricted grilling.
According to DEBKAfile’s counter terror sources, four questions should top the interrogators' agenda:
a) At what date did the Tsarnaev brothers turn coat and decide to work for Caucasian Wahhabi networks?
b) Did they round up recruits for those networks in the United States - particularly, among the Caucasian and Saudi communities?
c)  What was the exact purpose of the Boston Marathon bombings and their aftermath at MIT in Watertown?
d) Are any more terrorist attacks in the works in other American cities?