New Delhi, May 26 -- A string of measures - ban on biweekly visits from family members, segregation of new inmates to an isolated jail for the first 14 days and holding court proceedings through video conference from within the prison - has not been able to prevent the Covid-19 virus from creeping in to all three jail complexes in Delhi - Tihar, Rohini and Mandoli.

Till Monday evening, the three complexes, which house 14,000 prisoners and around 1,800 officers, reported 20 cases among prisoners and staffers.

Senior prison officers said contact tracing so far has revealed that in all the three jails, the virus reached the prison through asymptomatic jail officers.

At least 17 families living in separate flats at the Tihar residential comp...