Apparently depressed over Covid-19, a 61-year-old doctor allegedly killed his wife and children to "liberate them and remove all their troubles in a moment" at their apartment in Kalyanpur here, police said on Saturday.

Sushil Kumar, head of the department of forensic medicine at a private medical college, left behind a letter mentioning that he was suffering from an incurable disease and also that "Covid-19 will not spare anyone".