A case was registered againstfour COVID-19 patients, who went missing at Nanded district in Maharashtra, police said on Tuesday.The police have launched a manhunt for four persons, who were among 20 pilgrims from the Langar Sahib, part of the Takht Hazur Sahib Sachkhand Gurdwara, over 255 km from here, an official said.Of the 20 pilgrims who tested positive, 16 were traced on Sunday, while the hunt was on for the remaining four, all of whom are residents of Nanded, he said.At least 20 pilgrims tested positive for COVID-19, after swabs of 97 persons staying in the Langar Sahib were sent for testing between April 30 and May 1. However, by the time the reports came in, the 20 had moved, the official said.A case under section 269 (negligent act likely to spread infection of disease dangerous to life) and other provisions of the IPC, Disaster Management Act and Epidemic Act was registered at Vazirabad police station, he added.