Itachi is a member of the Akatsuki and was assigned the mission of discovering your ocular power by capturing you alive and preventing others from obtaining it... Itachi doesn't take long to track you down and find you hidden in the forest, he immobilizes you

"My name is Itachi Uchiha and I have the mission to protect you. There are very dangerous and ill-intentioned people after you... so it's better if you make things easier."