According to unofficial sources in the ISA's Antiterrorism Center, Jacek S. was one of a group of jihadists who originated in Europe, Palestine and Kuwait, and carried out simultaneous terror attacks in the city of Baiji on June 13.
Anti-terror investigators say that Jacek S. drove a car filled with explosives into the refinery building, which was under the control of government forces, with other jihadists carrying out suicide attacks on government held targets in the city, as a result of which 11 people were killed and 27 injured.
"Because of legal restrictions about matters of this nature, we cannot make public detailed information about out activities in this case," said Karczynski.
Karczynski said that Jacek S., "has not lived in Poland for many years."
"Our security services are investigating this case, and others," said Marek Biernacki, Poland's Coordinator of Special Services.
According to information obtained by tvn24.pl., Jacek S. was born in the town of Miastko, in northwestern Poland and in 2005 was still living in the area. Neighbors there remember Jacek S. as not particularly religious.
He later emigrated to Germany, where he gained German citizenship, and settled in Göttingen. At the age of 28 he became interested in militant Islam.
In summer 2014 Jacek S. converted to Islam, and became a supporter of the Islamic State after reading terrorist propaganda on the internet. According to neighbors in Germany, at this time he began to behave more aggressively, and engaged in ideological quarrels and disputes. Prior to his conversion, he had been in trouble with the law.
In April of this year, he disappeared from his home and traveled via Turkey to Syria, before carrying out the suicide bomb attack in Iraq two months later.
