All I know is that, so far,
I doubt that anyone else other than the organizers have a clear idea.
But there are some clues.
The planned demonstration was about peace and national dialogue, which in Turkey's incredibly fragmented and nuanced semiotics means that the participants were liberals, social democrats and people positively predisposed towards the Kurdish claims and the party that represents them, HDP.
In other words, PKK is highly unlikely to be behind this attack. They would gain nothing by attacking the segments that support the peace process. Plus, PKK has never fielded a suicide bomber. It is not their modus operandi.
The other suspect that the government is likely to turn to is the colossally stupid Revolutionary People's Liberation Party-Front or DHKP-C. Even though they were involved in a couple of suicide bombings previously, it would be hard for them to justify this one, as these people had nothing to do with the enemies they claim to fight.
That leaves two possibilities. The obvious candidate is ISIS. They have an army of zombie suicide bombers. And while it is not obvious why they would want to blow up these people, they certainly do not consider them friends or allies.
There is, however, one issue. And this one is relevant for the previous suicide bombing in Suruc a couple of months ago. ISIS claims its attacks. Not only that, it makes glorious videos about them. It interminably tweets about their exploits. It films its martyrs in Technicolor and puts them up on the Internet. It releases feature length movies about them.
ISIS has never claimed Suruc and it hasn't claimed this one.
That leaves one possibility.
Bulent Tekdemir, who was at the rally, told the BBC that the police used tear gas "as soon as the bomb went off", and "would not let ambulances through".
A local resident said that angry people tried to attack police cars after the blast. The HDP tweeted that police "attacked" people carrying the injured away.Which means that someone is trying to win these elections at all cost.
It is a crying shame.
It now looks like there were two suicide bombers.
Predictably, government sources are insinuating that the suicide bombers were ISIS idiots. Some pro-government papers are floating Arabic names as possible perpetrators. The problem with that theory is that, as I said in the main post, if they were, we would hear about them by now in a loud and clear manner.
Besides the police reaction in the aftermath of the bombing, there are two more pieces of evidence that point away from ISIS and foreign killers. A Turkish opposition daily, Cumhuriyet reported that a bearded man with a portable loud speaker kept telling HDP members to gather where one of the bombers eventually pulled the pin. He was speaking in Turkish.
This also suggests that HDP was the main target and I have no idea why ISIS would have a problem with them. PKK? Maybe, because of Kobani siege. But HDP is a political party with nothing to do with ISIS.
Secondly, the police, who normally search everyone in political rallies, did not conduct any searches. The Minister of Interior said that they were planning to do it at the main rally site. I don't have to tell you that this makes very little sense, as it would have been impossible to search thousands of people who were gathered in a big area. You do it at the gates on the way to the main arena.
One other thing. No police officers died or seriously wounded. While this might be just a fortunate coincidence, and good for them, it could fuel likely speculations that they knew where the attack was going to take place and studiously avoided that area.