The Central Reserve Police Force sealed one of its battalions and tested all 400 personnel of the unit on Thursday after a sub-inspector, who had been detected positive for Covid-19, died a couple of days ago.

Sources said the first casualty in the force, along with 52 positive cases so far, had set alarm bells ringing in the country’s biggest paramilitary force.

The 52 personnel include six who tested positive on Thursday.

The sub-inspector, Md Ikram Hussain, 55, a resident of Assam, died on Tuesday.

“The 31st battalion to which Hussain belonged has been completely sealed and all the personnel have been put in quarantine,” said an official.

An inquiry has revealed that the sub-inspector — who was diabetic and had blood pressure-related issues — contracted the virus from a nursing assistant in the force.

The nursing assistant, deployed with the 162nd battalion in north Kashmir’s Kupwara, was at his home on leave in Noida when he followed orders and reported to the closest battalion, the 31st battalion, stationed in Delhi.

On April 16 the nursing assistant developed influenza-like symptoms and was isolated and put in quarantine. He was tested the next day and the results, on April 21, confirmed Covid-19.

“As part of contact tracing, all those who had visited the unit hospital between April 16 and April 18 were asked to self-quarantine,” the official said.

The CRPF has been deployed in several parts of the country in Covid-19 relief operations and also to check the spread of the pandemic in certain areas, including the national capital.

All its formations across the country have been asked to contact-trace and quarantine personnel who might have come in touch with infected colleagues.

“The CRPF has now formed a Covid-19 management team that is headed by a commandant, which is looking into all advisories related to the force and also keeping a close eye on the health condition of the people who have so far tested positive,” the official said.