lelisa desisa came in first place with 2 hours , 9 minutes , 17 seconds .
caroline rotich of kenya won the women 's division with 2 hours , 24 minutes , 55 seconds after spring finish against mare dibaba of ethiopia .
security high at event two years after homemade explosives killed three near the finish line of prestigious race .
competition comes less than three weeks after boston bomber dzhokhar tsarnaev was found guilty of terrorism for explosions at 2013 finish line .