On 29 September, the Directorate of Security (Asayish) of the Kurdistan Democratic Party (KDP) in the city of Erbil was attacked by a group of six people, in which seven security officers were killed. So far, no groups have taken responsibility, but it is most likely that Al Qaida was behind it. They attacked the Kurdish Security forces of the KDP in May 2007. Kurdish media already reported the Islamic State of Iraq and the Levant (ISIS) and declared their responsibility for the attack, but they claimed responsibility in any official statement and said that why they attacked the Kurdish security forces. This led to a lot of speculations and conspiracy theories among Iraqi Kurds.
While Turkey has a large number of groups with different ideologies carrying out attacks, the numbers of suspects in the Kurdistan region are quite limited: Ansar al-Islam or Al Qaida.
The Kurdish Islamist movement emerged in 1987 with the creation of Islamic Movement of Kurdistan (IMK) that called for a Jihad against the Saddam regime in 1987 in the city of Halabja. After 1991, the party participated in the elections and also fought with the Kurdish nationalist parties. After the IMK was weakened and after being militarily defeated by the Patriotic Union of Kurdistan (PUK), splits started to emerge in the movement among the rise of groups such as Hamas (1997), Second Soran Force (1998), Tawheed (2000), Jund al-Islam (2000), and Ansar al-Islam that rejected participation in an electoral democracy.
In the 1990s, Islamists from Tawheed, Hamas, and Jund al-Islam (2001) engaged in attacks against Barzani's Kurdistan Democratic Party (KDP) and Talabani's Patriotic Union of Kurdistan (PUK) regions and carried out assassinations, attacks, . For instance, Tawheed assassinated prominent Christian KDP politician Franso Hariri, governor of Erbil, in February 2001. Most of their armed members were militants from the Afghanistan war (1979-1989).
The most known Islamist group is Ansar al-Islam. Its creation is the result for a merger of other Islamists groups such as Islah, al-Tawhid Islamic Front, and Jund al-Islam in December 2001. Before the US invasion of Iraq in 2003, the group was involved in violent clashes with the Patriotic Union of Kurdistan (PUK). However, the group was expelled from the Kurdistan region by joint cooperation between the PUK and US Special Forces in 2003. As a result, Ansar al-Islam's fighters dispersed to Iran and later returned to Iraq and renamed itself Ansar al-Sunna. In 2007, the group renamed itself back to Ansar al-Islam after tensions with Al Qaida by its leader Abdullah al-Shafii, the former leader of Jund al-Islam. The group refused to join and accept the leadership of Al Qaida's Islamic State of Iraq (ISIS). The group operates mostly outside of the Kurdistan region, and has weakened severely.
However, experts doubt that Ansar al-Islam is behind the attack. Aymenn Jawad Al-Tamimi, Shillman-Ginsburg Fellow at Middle East Forum and researcher on Jihadi groups , and Mohammed Baziani, an Islamic researcher based in Erbil  says it's unlikely that Ansar al-Islam was behind the attack, since the group has grown weaker, and operates mostly in Sunni Arab areas of Iraq. The last time Ansar al-Islam gained attention in Kurdistan was after the killing of a government critic. In September 2010, the Kurdish government blamed Ansar al-Islam for killing the 23-year-old student Sardasht Osman, who was critical of Masoud Barzani's rule . But Ansar denied responsibility, "If we kill or kidnap someone, we will announce it ourselves. We don't need anybody to lie for us."
Most likely the attack was carried out by the Al Qaida affiliated ISIS. A reliable pro-Jihadi Twitter account @said_alshami claimed Ansar al-Islam doesn't carry out operations anymore, and that the ISIS had nurtured battalions in Kurdistan . There were reports that Kurdish Jihadis from the province of Suleymaniyah headed to Syria, and a new group, the Kurdish Islamic Front fighting against PKK-affiliated groups in Syria, also consists of Kurdish Jihadis. Some Kurdish Jihadis from Iraq were captured by the PKK-affiliated People's Defence Units (YPG) in Ras al-Ain close to the Turkish border after they captured the city in mid-July. Also, Arab media reported 30 Kurds joined al Qaida in Syria.
According to Twitter user Said al-Shami, Al Qaida's Kurdistan Battalions have pledged allegations to Abu Omar al-Qurashi al-Baghdadi, the former leader of the Islamic State of Iraq (ISI). This group was designated as a Foreign Terrorist Organization by the U.S. Department of State on January 1, 2012 . The group drove a car bomb into the Kurdistan Interior and Security Ministries building in May 2007, and the security forces of the PUK prevented a suicide attack by the group in September 2010 . "Allahu Akbar [God is great]: and the Kurdistan Battalions which pledged allegiance to ISIS under the leadership of Sheikh Abu Omar al-Baghdadi (God accept him) have returned. #Erbil.", he Tweeted.
Another respected Jihadi account, @zhoof21, one of the most reliable unofficial pro-ISIS accounts on Twitter, also talked about the attack. "ISIS: Kurdistan explosion of three car bombs at headquarters of Asayish apostates on 60 streets in the town of Erbil, in addition to two suicide bombs on the HQ, with dozens of apostates were killed and wounded. This attack comes at a time when ISIS is engaged in fierce battles with the PKK [Kurdistan Workers Party] apostates in the provinces of Hasakah, Raqqa and Aleppo and Idlib in which the apostates have suffered heavy losses and the mujahedeen have seized a number of areas."
Nevertheless, the motive for the attack remains unclear. This is because no group officially took credit for the attack, and as a result there was a lot of speculation in the Kurdistan region. Especially because it just happened after the final election results were announced for the parliamentary elections.
Ceng Sagnic, a Kurdish senior intelligence analyst based in Israel, doesn't think it is linked to Syria, despite of claims by pro-Jihadist accounts on Twitter that it was revenge for Syria. "The KRG is not sending any support to the PKK. Logically, attacking the KRG for this reason has a strong potential to strengthen the relations of KDP-PKK, which is not preferred. Therefore, the reason should be bigger than the limited warfare between the PKK and Al Qaida."
Although Barzani said he would support Syrian Kurds against Al Qaida, if ethnic massacres were proven, in the end no forces were sent to help. In fact, the PKK was angered after the KDP concluded that no massacre happened in the countryside of Aleppo . Often, groups affiliated to the PKK in Syria accused the Kurdish Democratic Party of Syria (KDP-S) of conspiring against them. For instance, they accused the KDP-S of cooperating with anti-PKK insurgent groups in Çilaxa (Jawadiya)  in order to control oil-rich Ramalan.
Moreover, there are suspicions among the PKK-affiliated Democratic Union Party (PYD) that in Ashrafiya and Sheikh Maqsoud, Barzani-funded FSA groups fight against the PYD. Furthermore, members of pro-Barzani parties in Afrin were accused of carrying out an attack in which civilians were killed, and arrested by PYD's Asayish. Often, pro-PYD media accused both Turkey and Barzani of conspiring against the PYD. Thus, an attack by Al Qaida on Barzani-controlled Erbil could bring the PYD/PKK and the KDP more closely together. Following the attack, the PKK called on all Kurds to unite against their enemies.
Other suspects are Iran. There have been always suspicions that Iran from time to time used Jihadi groups to target their enemies. Iranian Kurdish politician Hussein Yazdanpana, vice president of Kurdistan Freedom Party said on the Kurdish TV-station NRT that the attack was decided in Teheran and the Iranian consulate in Erbil. Rudaw columnist Hiwa Osman said it could be revenge for the fact that Barzani refused Iranian Quds brigade commander Qasim Solaimani to move weapons through the Kurdish-controlled border to Syria . He also mentioned that another reason could be that the violence in the rest of Iraq, or from the war in Syria, has reached the Kurdistan region. Others point out that it could also be related to new security cooperation between Maliki and Barzani after they reached a deal in July 2013.
Despite of all this speculation and conspiracy theories, it is most likely that Al Qaida-linked groups are behind the attack. Al Qaida's media wing Al Furqan has published a video in 2010 called the Vanquisher of The Peshmerga [Kurdish security forces] in which Al Qaida accused Barzani and his father of waging a war against Islam . For Al Qaida, there is no difference between secular Kurdish parties and they see both the PKK and the KDP as secular enemies of Islam that focus on Kurdish nationalism instead of an Islamic state. With the weakening of Ansar al-Islam, it is most likely that Al Qaida's Kurdish battalions were involved, since they also recruit Iraqi Kurds and have the expertise and experience to carry out this kind of attacks, as they did in the rest of Iraq.