Sri Lankans are now wondering what the suicide bomb blast in the heart of the capital means for the country's fragile peace process.
The motive for the attack is still unclear
It is the first such incident since a Tamil Tiger blew himself up in 2001 when being questioned by police guarding the then Prime Minister, Ratnasiri Wickremanayake.
But - unlike attacks during the height of the war - the intention behind this one is still not clear.
The woman suicide bomber initially tried to enter the Ministry of Agricultural Marketing and Development and Hindu Affairs run by Douglas Devananda - a Tamil politician implacably opposed to the Tigers.
Mr Devananda may have been the target but it is hard to imagine how a suicide bomber thought she would get past the tight security that surrounds a man who has survived previous attempts on his life.
Another theory is that the bomber expected to be escorted to the police station and that was her intended target.
A wall of silence from the Tigers - despite still having telephone contact with the outside world - seems to confirm their responsibility for the attack which bears all the hallmarks of their organisation.
Recent weeks have seen increasingly angry statements from the Tigers.
Many within the establishment in the south feel the split in the Tamil Tigers is too good an opportunity to miss
They have repeatedly accused the Sri Lankan military of waging a covert war against them in the east of the island using the breakaway commander Colonel Karuna.
The Tigers blamed Col Karuna for several attacks in the east, including the killing of a prominent journalist and four disabled rebel fighters.
The situation escalated on Monday when one rebel official was shot dead and three others injured in two attacks inside government-controlled territory in the east.
The rebels accused the military of collusion in the attacks which took place on the day they commemorate the death anniversary of their first suicide bomber and honour the 240 other young men and women who followed him.
It looks as if this suicide bomb blast in Colombo is a message from the Tigers that they will not tolerate the situation in the east any more.
They believe the military has been aiding and abetting a man they consider a traitor to their organisation.
Col Karuna: Allegedly in cahoots with the military
Colonel Karuna was the second highest military commander in the rebel organisation until he broke ranks in March.
After a few days of internecine fighting in mid-April, he vanished.
Then four of his top female commanders escaped and held a news conference saying they had been in Colombo collaborating with military intelligence.
An opposition MP then admitted he had helped Colonel Karuna escape to the capital.
The Sri Lankan military still denies involvement in the growing scandal but a government minister admitted to journalists some military personnel must have been involved without the government's knowledge.
Douglas Devananda, who may have been the intended target of the suicide attack, has repeatedly said he has been in telephone contact with Colonel Karuna in order to help him establish a political party.
Many within the establishment in the south feel the split in the Tamil Tigers is too good an opportunity to miss.
They believe by backing Colonel Karuna they can weaken the rebel movement's grip on the east and undermine their claim to a Tamil homeland in the area and to be the sole representatives of Tamils.
The Sri Lankan military spokesman has said it is too early to say whether the bomb blast was an act of war by the Tigers.
The assumption is if the rebels meant to start the war again it would be with a series of simultaneous bombings, not just one.
There is, however, no doubt this is the most serious threat to the ceasefire since it was signed in February 2002.