India, Feb. 15 -- Four executives of a sub-contractor and an executive of a consultant firm have been arrested after a slab of the under-construction Metro line 4 collapsed, killing one person and injuring three others in Mulund on Saturday afternoon.

Four of the executives arrested are with Milan Road Buildtech, a firm sub-contracted by a consortium comprising Reliance Infrastructure Limited and Astaldi of Italy. They are: project director Harish Chauhan; project manager Kuldeep Sapkal; deputy project manager Saurab Singh; and supervisor Prashant Bhoir. The fifth individual arrested, Avdhoot Inamdar, is project manager at Hill International Inc.

The concrete slab toppled onto a moving autorickshaw, in which Ramdhan Yadav, the deceased,...