Jose Maria Aznar, the prime minister of Spain, is accused of covering up the investigation of the recent terrorist attacks, particularly possible links to Islamic extremists.
The reason, why Aznar and the Spanish government are holding back important information, is an easy and at the same time shameful one: They want to win a fucking election.
Right now they are telling the constituency that the ETA is most probably responsible for the attacks, because they hope to gain a bunch of votes from this: The ETA has been a pain in the ass for Spain for decades, and if the government tells people that this pain in the ass is also responsible for one of the most shocking assaults ever and that they will be combatted without mercy, then people will most probably vote for the current governement, because they trust them.
Instead of telling the truth (*), the government leaves the bereaved in a terrible incertainty: Did the ETA kill their loved ones or are islamic extremists responsible for this crime? While the answer to this question will neither make the bereaved more happy nor make the dead alive, I can imagine that knowing the cluprits would be quite a relief for them.
All in all, this just another example, where craving for power ranks higher than ethics and interpersonal honesty.
(*) There have been numerous videos and messages from organization that are closely related to al Qaelda, in which people (no ETA members) confess to be responsible for the attacks.