According to De Facto, Mārtiņš spent several months in a Syrian prison after he went silent on social networks last November. He managed to escape but was arrested after crossing the border into Turkey.
About two weeks ago Mārtiņš was deported to Latvia, and now he's facing charges over illegally fighting in an armed conflict abroad, punishable by up to ten years in prison.
His situation however is not simple. A person who had met Mārtiņš following his return to Latvia told De Facto that he doesn't have a lawyer. The Latvian Security Police responded to De Facto only after a repeated request, saying that "all the norms of Criminal Law were considered" and that "the suspect is informed about his right to a defense."
There is little reason to think that Mārtiņš is well-informed about Criminal Law, meaning he could be facing a swift trial without proper defense in court.
Mārtiņš left Latvia in September 2014 but the Criminal Law article over fighting in an armed conflict abroad was introduced in February 2015. This would mean that upon leaving Latvia and possibly fighting for Islamic State he did not break the law.
Mārtiņš turned to Islam in summer 2013 after finishing grade 11. He had no friends at school but he had made a Finnish friend on the internet at a video game forum. They both signed up at a large Muslim forum where they were active posters until Mārtiņš left Latvia.
For example, on November 13, 2013 Mārtiņš wrote that he had just converted to Islam, asking others for advice on how to practice the religion despite living with his parents and facing an anti-Islamic father.
While it's possible that he had been a supported of Islamic State even then, Mārtiņš' earlier posts on the forum mostly relate Mārtiņš' everyday activities and testify to his interest in Islam.
Mārtiņš' teacher told De Facto that "[Mārtiņš'] world centered on the internet and the computer" while a store clerk at the village where he lived described him as "more of a loner". He did not attend events at school and was not present for his graduation party. He also stopped listening to music.
His forum posts grew increasingly irate and showed support for Islamic State. He also became more interested in jihad and martyrdom.
One of his posts, for example, claims that the EU is an Illuminati project. Another demands for a Caliphate to be established.
In another post he asks whom he could save should he become a martyr, because none of his relatives are Muslim. Other posts praise Osama bin Laden and the Islamic State.
The posts of Mārtiņš and his Finnish friend ceased on the same day in August 2014, and later on the Finn told YLE that he had joined the Islamic State with his sole friend - a young man from Latvia - after going to Syria in late September. The Finn claimed that he had not participated in combat but was on guard duty.
Mārtiņš did not respond to De Facto's inquiries as to his whereabouts and lied about his location and activities to an acquaintance.
Here's an excerpt from a November 21, 2015 exchange with his friend Jānis (name changed):
Jānis: What are you doing there?
Mārtiņš: I'm working, helping refugees, doing independent journalism, etc. [...]
Jānis: When are you returning to Latvia?
Mārtiņš: I can't at the moment, I'm busy.
It's not known whether he kept in touch with his family. Last year his father denied having a son to De Facto while his mother chased journalists away with a stick as they visited last week.
The Security Police are currently investigating three instances of persons from Latvia participating in the Syrian conflict.