An Indian engineer was killed and three foreign workers others injured today in a shooting spree in an oil field operated by a Canadian firm in south-eastern Yemen, witnesses said. The attacker armed with a rifle opened fire randomly at the men in Jannah oil field in Shabwa province, 400 kilometres of south of the capital Sana'a. The attacker was arrested on the spot. No motive was immediately known, according to a report of Deutsche Presse Agentur (DPA).