Bismillahir Rahmanir Rahim.
Islam assures equal rights and protection of the life, honour and property of any non-Muslim resident in a Muslim state; there is no difference between them as human beings. It is for this reason that Islamic law outlines equal treatment to both Muslims and non-Muslims in the matters of blood money and retaliation (qisas). Non-Muslims have equal personal and religious freedoms in a Muslim society. Their places of worship also enjoy complete protection.
The protection of life and property of non-Muslim traders is as the Muslim traders, the responsibility of the Muslim State. Islam does not allow or advocate using violence against and the killing of peaceful and non-combatant citizens under any circumstances. Those carrying out attacks on non-Muslim citizens; kidnapping them for ransom and torturing them mentally or physically are in fact committing a serious violation of the teachings of Islam and Islamic law pertaining to the rights of a non-Muslim resident in a Muslim state and will themselves be breaking the law and deserving of the necessary judicial penalty.
And Allah(swt) alone knows best.