Despite his youth, he reportedly reconnoitred potential target sites "like a professional". He is not believed to have built any bombs by the time of his arrest, but he had researched bomb-making extensively on the internet, and made specific inquiries about purchasing certain parts.
The Austrian authorities have spoken only of "unconventional explosive devices", but, according to local media reports, he was planning to build improvised cluster bombs similar to those used in the 2013 Boston marathon bombings.
It appears he was not planning a suicide attack: he has reportedly confessed that he wanted to travel to Syria to fight alongside jihadist groups there, and saw a successful bombing campaign as his ticket to join. A report in Kronen Zeitung newspaper claimed he was actively recruited over the internet by Isis and promised a "special position" as a reward for carrying out the bombings, as well as the payment of US$25,000. The newspaper claimed two other youths were recruited to carry out attacks in similar fashion and remained at large.
But other local newspapers reported that Austrian investigators believed Mertkan G may have been a so-called "lone wolf", working entirely on his own. The boy, who lived with his parents in St Polten, a small city not far from Vienna, was known locally for speaking out in favour of Isis and other jihadist groups, but the reports said his friends did not take him seriously.
