After searching for an image posted on Facebook, I found one English news article, speculating he defected from Assad's forces and immigrated to Finland. FINLAND: ASYLUM SEEKER IN TORNIO SHOWN STANDING ON HEAD
The patch on his jacket is of The Islamic Movement of Iraq, and he is also pictured behind a backdrop of the standard ISIS/ISIL logo. Islamic Movement of Iraq
I searched for these images, and found some Finnish news articles, some saying he was arrested by the Finnish police for being a terror suspect. His name is Ammar Jebbar-Salman, or Ammar Al-Ziadi. Here is the Tampere arrested 29-year-old war criminal! Is this a killer now in Finland as an asylum seeker? Ammar Al-Ziadi, decapitating infiltrated the Iraqi refugee
Here is his Facebook profile, and the original posts of some of those images (change koobecaf to facebook)
Post 1 https://www.koobecaf.com/photo.php?fbid=1648116335415530&set=a.1416855118541654.1073741828.100006515387104&type=3
Post 2 https://www.koobecaf.com/photo.php?fbid=1647259372167893&set=a.1416855118541654.1073741828.100006515387104&type=3
Post 3 https://www.koobecaf.com/photo.php?fbid=1659839887576508&set=a.1416855118541654.1073741828.100006515387104&type=3
Most of the comments on these images are "You're a hero", "May god preserve you", and such words of encouragement. I don't know what percentage of civilians support them, but judging by these responses they don't seem too unpopular.
Here he posts a video with text that translates to "Of the Tikrit Battle"
Tikrit Video https://www.koobecaf.com/100006515387104/videos/vb.100006515387104/1691168817776948/?type=2
"The Second Battle of Tikrit was a battle in which the Iraqi forces recaptured the city of Tikrit (the provincial capital of the Saladin Governorate) from the Islamic State of Iraq and the Levant (ISIL)."
"The offensive is the largest anti-ISIL operation to date, involving some 20,000–30,000 Iraqi forces (outnumbering ISIL fighters more than 2-to-1), with an estimated 13,000 ISIL fighters present. It was reported that 90% of the residents of the city left out of fear both of ISIL and retaliatory attacks by Shia militias once the city is captured. As such, most of the residents fled to nearby cities, such as Baghdad and Samarra, or even further to Iraqi Kurdistan or Lebanon." Second Battle of Tikrit
So it's likely a good portion of the migrants are people who fled Tikrit and surrounding areas once the Islamic State drove out ISIS. At least a significant portion of these people were ISIS supporters and, judging by this incident, there will be ex-ISIL fighters hiding in the masses. Though some not hiding very well, if he was dumb enough to post his current migration status after positing pictures of him stepping on a guy's severed head. If he was arrested by the Finnish authorities, they seem to know what's up.