Sandeep Singh (41), a businessman from Varanasi, Uttar Pradesh, India, has been poisoned with thallium, a rare and highly toxic substance, leading to an attempt to murder case filed by police. The FIR was lodged at the Kotwali police station following a complaint from his wife, Khushboo Singh. The investigation is focused on how the poison was administered, with suspicions arising during his travels and business meetings. Singh, who runs two transport firms, began experiencing severe symptoms in late February 2025 while in Gurugram, including fever, tingling in the legs, and vomiting. After being treated in multiple hospitals, toxicology tests confirmed thallium in his bloodstream. Medical experts have highlighted the challenges in detecting thallium, which is colorless, odorless, and tasteless, making it difficult to identify when mixed with food or drink. The police are currently investigating the case, which has raised significant concern due to the nature of the toxin.