Agenda: Constructive ambiguity has served Sinn Féin and the IRA well in the peace process. Now, as the British and Irish governments seek an unambiguous end to all IRA activity, the republican movement continues to face both ways on a key matter that will not go away - the killing of Robert McCartney. Peter Murtagh reports from Belfast

The reaction of Sinn Féin and the IRA to the killing of Robert McCartney fell into three broad categories.

First there was the cover-up and intimidation. This was orchestrated by Gerard Davison, a senior figure in the so-called Belfast Brigade of the Irish Republican Army, the military wing of Sinn Féin, who is well known to Gerry Adams and other senior members of the Sinn Féin leadership.

Davison, who is known to his associates as "Jock", and who has a record as an IRA member, was involved in the fight in Magennis's bar that preceded the assault outside the pub in which Mr McCartney died. At one stage during the melee, Davison is reputed to have glanced at some of his IRA associates and to have drawn his finger across his throat, a signal as to what he wanted done to Mr McCartney and his friend Brendan Devine.

In the immediate aftermath of the fight and killing, two car-loads of IRA people came to the bar. They, together with members of Sinn Féin, were directed by Davison in cleaning the bar to remove any forensic evidence that might have been useful to the police.

They were mainly, but not entirely, successful.

Over succeeding days, several people who witnessed events inside and outside the pub were visited by IRA members, some of whose identities are known to The Irish Times, and told to shut up. Nonetheless, the McCartney sisters and Mr McCartney's partner Bridgeen Hagans maintained public pressure on republicans and continue to do so.

On February 25th, the IRA issued a statement in which it said that it and the "Belfast Command" had "court-martialled" and dismissed three "volunteers, two of whom were high-ranking volunteers".

Davison was one of the high-ranking "volunteers" but his dismissal did not, apparently, make him persona non grata with all republicans. A few days after his "expulsion" Davison outed himself in an interview with Daily Ireland, the Belfast newspaper strongly supportive of Sinn Féin.

In an interview which even Daily Ireland described as self-serving, Davison admitted he was in the bar but denied any involvement in the attacks on Mr McCartney. (Other sources say that Davison smashed a bottle over Brendan Devine's head, during which he cut his own hand - an injury transmogrified by Davison into a knife attack on him which caused him to leave the bar for hospital treatment before Mr McCartney's death.)

After his "expulsion" Davison was seen in the Short Strand getting high-profile public support from Bobby Storey, a close associate of Adams. Storey pointedly walked the area side-by-side with Davison.

Storey is a long time-member of the IRA and was named this year in both the House of Commons and the European Parliament as the brains behind the Northern Bank raid. He is a member of the IRA's so-called General Headquarters Staff and was characterised as having overall responsibility within the IRA for intelligence matters.

Despite his alleged expulsion from the IRA, Davison also remained evidently acceptable to Sinn Féin candidates in the May Westminster and local elections: he was seen canvassing on behalf of several of them.

Davison, who has no job or visible means of support, but is reputed to own property in central Belfast and the Co Down seaside village of Killough, is now believed locally to be in the United States.

The second response to Mr McCartney's death was to go on the offensive by attacking the police.

The incident in Magennis's happened on Sunday, January 30th, and Mr McCartney died in hospital early on Monday the 31st. Magennis's is in central Belfast, very close to the Royal Courts of Justice, about half-way between two inner city republican strongholds, the Markets and the Short Strand.

The two communities are close in that some people living in one previously lived in the other. There is a degree of inter-marrying between people from the two areas.

So following the dramatic and bloody death of Mr McCartney, it was not long before there was widespread knowledge that republicans were involved, either directly as participants or indirectly as witnesses.

On January 31st, however, Alex Maskey, the Sinn Féin councillor for Laganbank, blamed Belfast's knife culture for what had happened and went on to attack the police. "This case is a tragedy, particularly for the dead man's family and friends," said Mr Maskey, who is also a Sinn Féin Northern Ireland Assembly member and former Lord Mayor of Belfast. "Local people are shocked and saddened at this incident."

And then he had a go at the Police Service of Northern Ireland who went to the Markets area seeking evidence but were forced to withdraw after being attacked by stone-throwing youths (who some local sources suggest were put up to it by republican activists).

"It appears," said Mr Maskey, "the PSNI is using last night's stabbing incident as an excuse to disrupt life within this community and the scale and approach of their operation is unacceptable."

Any suggestion that local leading Sinn Féin members did not know that some of their closest local party colleagues were in Magennis's bar seems improbable.

One of the men most deeply implicated in the whole affair was, until recently, a senior party officer in a Sinn Féin branch in Maskey's political back yard. That person cannot be named here for legal reasons. Another Sinn Féin member in the bar, Deirdre Hargey, was designated as Maskey's running mate in the then pending local elections. In the furore that followed, Hargey was removed from the Sinn féin ticket.

Yet another Sinn Féin member in the bar was Seán Hayes, a former Belfast City councillor and Assembly election candidate. Mr Hayes also "outed" himself in Daily Ireland.

"I was in the bar the night Robert McCartney died," said Mr Hayes. "After the whole incident was over, the PSNI came in and took everyone's names. They didn't ask anyone to leave the bar or attempt to turn it into a scene of a crime."

This was maybe because it did not look like a crime scene given the Sinn Féin/IRA clean-up to remove broken glass, blood, fingerprints and anything else that might have aided the police catch the culprits.

But the third, and most sustained, form of reaction since a February 14th statement by Gerry Adams has been to empathise publicly with the McCartney family's quest for the truth and urge anyone with information to come forward, or as Gerry Adams has put it "provide full and frank statements".

But what evidence is there to support Sinn Fein's contention that the party is sincere in wishing to support the McCartney family - which must, inevitably, mean supporting the processing of some of its members, and members of the IRA, through the courts of Northern Ireland?

Both Sinn Féin and the IRA say they have taken action against members who have not done as required - ie "provide full and frank statements" to the police via the office of the Police Ombudsman. Sinn Féin claims to have suspended a number of members while the IRA has said it dismissed three "volunteers" and, later, told the McCartney family it was willing to "shoot the people directly involved in the killing of Robert McCartney".

On the basis of available evidence, that would not have included Jock Davison.

On February 24th, the McCartney family gave Gerry Adams the names of several Sinn Féin people they said were in the bar. The precise number of names given at that time is difficult to determine: the family say it was six, to which they say Adams added one more making seven - all of whom he said were "suspended" from the party.

In a statement on March 3rd, Adams said "seven of those named [ implying named by the family] are members of Sinn Féin". (Since then, the family has created a list of 20 SinnFéin members they say they believe were in the bar.)

Adams' March 3rd statement continued: "Those named by the family are suspended from membership and from any involvement in Sinn Féin activity pending the outcome of the legal process . . . All of these people have been personally instructed to provide full and frank statements".

By April 24th, however, Adams had a different number of suspensions.

In a statement stating that "Sinn Féin is continuing to do all that we can to help the McCartney family", Adams noted how he had "called on everyone who was in the vicinity of Magennis's bar to provide full and frank statements", and he added the following:

"Because Sinn Féin takes this matter so seriously, we suspended the 11 members of the party who were in the bar that night and the one who later arrived on the scene."

In a statement to The Irish Times in response to a number of detailed questions, Sinn Féin said that of the 12 suspended, "four resigned and two were expelled" for refusing to adhere to Adams's instruction. And the statement then added: "None of these individuals were among the seven party members whose names were given to us by the McCartney family last February."

Thus, on March 3rd, Gerry Adams says that seven people named by the family were suspended; family members say they named six people. By April 24th, Adams put the number of suspensions at 12.

It its statement to The Irish Times, Sinn Féin says that none of the 12 came to the attention of the party via the McCartney family. All of which raises the question, what happened to the people named to Sinn Féin by the McCartneys?

Unlike other political parties disciplining errant members, Sinn Féin refuses to name the people it says it suspended, or those reinstated or anyone else who remains suspended, resigned or expelled. They claim this is because legal proceedings are pending.

"We do not intend to name any individuals publicly nor will we do anything that would jeopardise legal proceedings," said Sinn Féin's statement to The Irish Times, adding: "Our lawyers have advised us not to release the names of any of these names publicly."

Two of those suspended have in any event identified themselves - the former councillor Seán Hayes and Alex Maskey's dumped running mate, Deirdre Hargey.

Asked by The Irish Times why, in reinstating five members, Adams had not adhered to his commitment of March 3rd that people suspended would remain suspended "pending the outcome of legal proceedings", Sinn Féin did not respond.

As to the substantive matter of "full and frank statements" to the Ombudsman, the picture seems to be other than the party is projecting.

According to sources outside Sinn Féin, 12, possibly 13, statements have been given to investigators attached to the Police Ombudsman's office by the solicitor acting for Sinn Féin. However, they are not much use to the police investigation.

Several are not signed and, most tellingly, the statements are so limited in content that they are of little evidential value. In several instances, they contain little more than confirmation that the maker of the "statement" was in the pub but saw nothing. The explanations offered vary but include assertions that the maker was in the toilet or was at the bar, or was looking the other way and hence saw nothing.

Such assertions lack credibility. The picture of what happened inside the pub, from second-hand accounts to The Irish Times and other media, including RTÉ's Prime Time recent re-enactment, is one of a space crowded with people in which extreme violence occurred, involving breaking glass, blood and overturned furniture. Ombudsman and PSNI investigators find it difficult to accept that "statements" offered to date tell anything like the full story that the person making them could tell were they really co-operating fully.

To date, only one person, a female member of Sinn Féin, has submitted to a follow-up interview with the Ombudsman's office. This was held in March at the request of the PSNI. What happened is perhaps instructive to the level of co-operation, or lack of, that has followed.

The woman, whose identity is known to The Irish Times, was questioned in great detail. The questions sought to establish and verify facts such as who was in the bar and the sequence of events prior to Mr McCartney, Mr Devine and a third men with them, Ed Gowdy, leaving the pub.

The list of questions provided by the PSNI was very lengthy and probed what precisely was going on in the bar, who was standing or sitting where, and sought to establish a verifiable sequence of events leading to Mr McCartney's death in an adjacent alleyway, Market Street

But following this probing interview, the shutters came down. Suddenly, the Ombudsman's office found that other members of Sinn Féin did not want to come forward. It seems that either the people who made initial vague statements had no intention of co-operating further. Or, when the depth and extent of follow-up questioning became apparent, they reverted to their original position, which was, in effect, not to co-operate fully while seeming to do the opposite.

"The party president [ Gerry Adams] has repeatedly called on everyone with information to make it available," says Sinn Féin's statement to The Irish Times. "We have worked hard on the ground to create the climate in which this can happen."

The McCartney campaign for truth has been articulated mainly by two sisters, Catherine and Paula. Paula McCartney sits in the living-room of her modest Short Strand home on a hot, sunny afternoon; Catherine is beside her, and her other sister, Claire, is there too.

Noisy, dusty traffic moves up and down the Albert Bridge Road outside. Children scamper in and out of the room. The three sisters say they cannot understand why Sinn Féin has reinstated suspended members.

"From their point of view", says Paula, "there's no media spotlight now and two people have been charged. So why did they lift the suspensions on the five?"

They have asked to meet the Sinn Féin leadership (Adams and another high-ranking party member Gerry Kelly have met the sisters a number of times) to discuss the reinstatements.

"We want clarity on the suspensions and we want answers to the 18 questions we gave them by email in April and by hand on May 1st," says Catherine.

She says also they were told there would be an internal Sinn Féin investigation and that the results would be made public.

In its statement to The Irish Times Sinn Féin said a meeting with the family would be arranged to discuss the reinstatements. As regards the 18 questions, they were answered on April 24th, said the party, and also made public.

Two men with strong links to the republican movement have been charged in connection with Mr McCartney's death. Terry Davison and Jim McCormack are being held on remand in Maghaberry Prison. According to Gerry Adams, true republicans acting in the name of their creed cannot, by definition, be criminal. Sinn Féin now categorises the killing of Mr McCartney as a crime.

Terry Davison and Jim McCormack are being held in a wing of the prison reserved for republicans. That, says Sinn Fein, is nothing to do with them.