AN EXTRAORDINARY week or so in Croatia. Parliament has been dissolved and on October 31st President Ivo Josipovic called elections for December 4th. It was announced that ruling Croatian Democratic Union (HDZ) is being investigated for corruption. Ivo Sanader, the former head of the HDZ and prime minister went on trial and independent Croatia's first interior minister was arrested on charges of murders allegedly committed in 1945. (He denies all wrongdoing).

What to make of all this? In June Croatia received the go-ahead to join the European Union in 2013. The country did a huge job in modernising and reforming the state in order to be able to join. A big bit of that was to strengthen the judiciary and to show that everyone was equal before the law and that the executive did not interfere with the work of the judicial authorities.

At the beginning few believed that these reforms would really mean that people at the very top would come under investigation, let alone go on trial. They were thus shocked when Ivo Sanader, prime minister from 2003 to 2009, was indicted and then arrested in Austria last December as he tried to flee. Finally his trial has started. The heart of the case is the allegation that Mr Sanader received backhanders from the Austrian bank, Hypo-Alpe-Adria, which I wrote about last year.

Mr Sanader told the court that he denied “the charge of being a war profiteer with repugnance. I always served my country and my nation.” Early indications suggest that his line of defence is going to be that, if there was any wrongdoing, it was done by others, including Mate Granic, the former foreign minister. In the wake of Mr Sanader's arrest all sorts of allegations against have been made against him, including receiving piles of cash in paper bags.

The irony of the case is that it was Mr Sanader who modernised the HDZ and set it on the course for European accession which necessitated action against corruption. It was then his successor, Jadranka Kosor who opened the way for investigations into Mr Sanader and other top officials. Now that has come back to haunt her. The HDZ is under formal investigation by the country's anti-corruption agency over party financing during the elections of 2003 and 2007 and the presidential election of 2005, when Mrs Kosor was a candidate. Its critics say that this is the tip of the iceberg.

Mrs Kosor is not personally under investigation. She told journalists however that the announcement was “one of the hardest days for our party. This is an attempt to demolish the HDZ.” All this is fantastically good news for Kukuriku, the opposition coalition, whose title translates as “cock-a-doodle-do”. It is drawn from the name of the restaurant where the leaders originally met, but was clearly chosen to symbolise a clarion call to Croats to wake up, and vote for them. And the latest opinion polls indicate they look set to do that. They put Kukuriku on 40% with the HDZ on 20%. Mrs Kosor had an approval rating of 26% while Zoran Milanovic the leader of the Social Democrats, by far the largest Kukuriku party, was on 46%.

The HDZ has responded to this by shifting its rhetoric and actions into a more nationalistic mode, harking back to the war years of the 1990s, in the hope of regaining the trust of voters. But, Vesna Pusic, a veteran opposition leader chortles that this tactic is not working, “because the public associate the HDZ with grand theft.”

Some were not surprised then by arrest on November 2nd of Josip Boljkovac, the minister of interior when Croatia declared independence in 1991. Mr Boljkovac, who is almost 91, was like Franjo Tudjman, the then president and HDZ leader, in that he too had been a Partisan in Tito's victorious communist army, which took control of Yugoslavia at the end of the second world war. During the war Croatia was run by the Ustasha quisling regime.

In 1945 then the Partisans killed thousands of Ustashas, Serbian Chetniks and others deemed to have collaborated with the Nazis and Italian Fascists. Mr Boljkovac has been arrested on charges of “command responsibility” for the death of 21 people in May 1945. His lawyer, Ante Nobilo, says the charges are “shameless”.

On the face of it the arrest of Mr Boljkovac must rank as one of the wackiest things ever done in post-independence Croatia. Governments have not pursued elderly Ustashas. And, of course, Mr Boljkovac was considered good enough for Mr Tudjman, who after all, realised the Croatian nationalist dream of independence.

Two other 91 year olds are under investigation for similar alleged crimes. One is Josip Manolic, who was prime minister when Croatia declared independence in 1991 and the other is Rade Bulat, accused of war crimes dating from 1943. He says that without orders from the top, “nobody could be liquidated.”

Ines Sabalic, a well known Croatian journalist says the answer as to why they were deemed acceptable for Mr Tudjman was that he believed in reconciling the Ustasha and Partisan parts of the Croatian heritage. If innocent people were killed in wars, well he considered that that was just an unfortunate consequence of conflicts.

Some commentators in the region have linked the arrest of Mr Boljkovac to the image of the HDZ and the election, especially in the wake of the trial of Mr Sanader. However, others are speculating that this is not the case. Of course it is not that 20 years after independence and 66 years after the alleged crime was committed the zealous and speedy Croatian police suddenly found the smoking gun they have been looking for. No, but according to the principle of cui bono or “who benefits” one might consider the position of Tomislav Karamarko, Croatia's Minister of Interior who has been vocal on the subject of pursuing these men.

Some believe that far from being anything to do with the general election, the arrest of Mr Boljkovac, and perhaps others like Mr Manolic, whom incidentally, Mr Karamarko once worked for, is connected to post-electoral politics. That is to say that after what today looks like the inevitable defeat of the HDZ, Mrs Kosor will be swept from leadership of the party and Mr Karamarko will be in a strong position to take over. If he has some former communist scalps in his bag, then regardless of how old they are, this will bolster his credentials amongst the nationalist hardliners who have felt pushed to the margins under Mrs Kosor. So, all in all, a story that is set to run and run.