Saturday, Oct. 16, apparently out of the blue, the powers-that-be in Washington released a new revelation to the local media (first to the Washington Post): Five years ago, David Coleman Headley's wife informed the FBI that her Chicago-based husband was a key figure in the planning and preparation of the terrorist plot that killed 174 people in Mumbai, including six Israelis, in 2008.
Her tip preceded the attack by three years.
She was revealed as having given three interviews to FBI agents in which she related that Pakistan-born Headley was an active operative in Al Qaeda's most effective affiliate, the Pakistani Lashkar-e-Taibe, had trained in its Pakistan camps and shopped for night-vision goggles and other equipment.
His wife came forward, according to the reports, after a domestic dispute that resulted in Headley's arrest in 2005. She described him as bragging of working as a paid informant for the US Drug Enforcement Agency while he trained with terrorists in Pakistan.
Federal officials did not deny this suggestion. They were quoted as saying the FBI looked into the tip but declined to say if any action was taken.
DEBKA-Net-Weekly has followed the Headley case from its outset.
On Nov. 22, 2009, on the first anniversary of the Mumbai outrage, DEBKA-Net-Weekly 422 reported under the caption: Al Qaeda in America:  A Chicago Master-Cell Plots Attacks in India and Denmark:
An undoubtedly authentic al Qaeda-linked terror cell has been uncovered in Chicago. Approximately five years after 9/11, a group of former Pakistani Islamists, some of them US citizens, set up shop in a Chicago grocery store. The FBI discovered the group had been working for at least three or four years with one of al Qaeda's operational arms, Lashkhar-e-Taibe, as master planners of overseas operations - though not so far in their adopted homeland. 
From this headquarters they mapped out a series of plots against overseas targets in conjunction with the Pakistan-based terrorist organization. Their latest target was to have been the Danish newspaper which ran a series of cartoons of Prophet Mohammed in 2005 which enraged Muslims worldwide.
This year, on April 2, DEBKA-Net-Weekly 439 discussed the possibility of Headley's employ by the US as an undercover double agent:
India finds it hard to believe that US terror experts were ignorant of Headley's role as key man in the planning and selection of targets for the attack [in Mumbai] and the dispatch of the Lashkar-e-Taibe terrorists for its execution.
These suspicions have led New Delhi to the supposition that Headley was a double or triple agent working for
US intelligence, Pakistani's Inter-Services (military) Intelligence - ISI and also al Qaeda.
While Washington did indeed tip off Indian intelligence to the impending Mumbai attack two months in advance, the Indians now suspect that it withheld information which could have prevented the attack so as not to expose Headley.

debkafile's counter-terror sources wonder what the motivation was behind the release of a supposition that was widely aired in Israel and India at the time. Two possible answers are suggested here:
One:  The federal authorities are anxious to distract American public attention from the court procedures beginning last week in the case of the Palestinian-American Major Nidal Malik Hasan accused of murdering 13 US servicemen at Fort Hood base on Nov. 5, 2009 and responsibility for the most deadly Islamist terrorist attack every staged in a US military installation.
Several of the soldiers wounded in the attack, some very seriously, disclosed that their US base commanders had ordered them then and there to hold back testimony of jihadi terror and erase video photos of the attack recorded on their cell phones. No visual evidence of the attack has therefore survived - only the testimony of witnesses, one of whom confirmed that throughout his shooting rampage, Nidal never stopped shouting Allah is Great!
Our sources also confirm that the emergence of a Palestinian terrorist willing to carry out a massacre inside the United States is highly embarrassing for the Obama administration at a time when its diplomats are working hard to revive peace diplomacy in the Middle East.
2.  The US administration came under heavy fire for the unspecific, imprecise terror alert the State Department issued the whole of Europe on Oct. 3 against Mumbai-style multiple terror attacks. Three weeks later, most counter-terror agencies in Europe are certain the alert was unfounded and hurt Washington's credibility.
By releasing new data on the Headley case, the Americans hope to prove to the Europeans that they have learned their lesson from the Mumbai atrocity and were no longer repeating the mistake of disregarding incoming tips.
Their warning to Europe was based on information garnered from the jailed German al Qaeda operative Ahmad Wali Siddiqui. This time it was taken seriously.

More info here: