JORHAT, May 3: With an increase of the leopard population in the Gibbon Wildlife Sanctuary, the frequency of leopards attacking humans or vice-versa has commensurately increased near the sanctuary. Last night one Kamal Hazarika was attacked by a leopard at Kachogoral, Sonarigaon and on March 6, a leopard was killed after it attacked and injured four persons at Duliagaon and had killed a calf.