Security forces in Europe have been on high alert following reports that Younes Abaaoud, younger brother to the mastermind of November's Paris attacks, Abdelhamid Abaaoud, had left Syria and is en route to Europe in order to avenge his brother's death.According to Paris Match, a phone call intercepted by Interpol in late February caught Younes mid-conversation with his sister, Yasmina, who resides in Belgium. "I come here at 10 o'clock" were the words which caught the attention of security forces, who feared that the younger Abaaoud may be plotting a revenge-terror-attack.The younger Abaaoud has long been hailed by Islamic State as its youngest Jihadi. In January 2014, he was swept out of Belgium at the age of 13 and taken to Syria by his older brother Abdelhamid in order to join the ranks of IS. The terrorist organization flaunted the young recruit in propaganda material, posting photos of the youngster armed with a Kalashnikov and smiling.The Interpol file on Younes described the youth as a "terrorist," "war jihadi," and "killer," according to Paris Match. He was reported a "dangerous," "missing minor," who must be "stopped and detained immediately."Security forces believe he may have adopted an alias identity and changed his appearance - making it easier to slip through border controls throughout Europe and more difficult for authorities to stop him. They fear he may be making his way to a Turkish, Moroccan, or European destination, and that he will take advantage of the European Union's free movement policy to move from country-to-country unnoticed.The French Interior Ministry has denied having any knowledge of the Interpol report, and of Younes Abbaaoud's suspected return to Europe, according to Paris Match.