MADURAI: A 34-year-old man in Tamil Nadu ’s Theni district, who was in home quarantine , ran out of his house on Friday night and killed a 90-year-old woman by biting her throat.Police said the man, who had returned from Sri Lanka a week ago, was “mentally disturbed” after being home quarantined to rule out Covid-19 . He is a textile trader, according sources.Late on Friday, the man ran out of his home naked and bit the throat of Natchiammal who was sleeping outside her home. Hearing her cries, neighbours came to the spot and secured the man. He was handed over to police.The woman was admitted to Theni Government Hospital, where she died.