A police officer patrolling thestreets to ensure lockdown for containing coronavirus suffered head injuries when a motorbike-rider knocked him down in Maharashtra's Palghar district on Wednesday, officials said.A police team spotted a 20-year-old man, identified only as Rajbar, riding a two-wheeler near Evershine Nagar but when they tried to stop him, he allegedly tried to flee and knocked down sub-inspector Sanil Patil (27).Patil was rushed to hospital. He was found to have fractured his skull, said a police official of Waliv police station.Rajbar was arrested and booked under IPC section 353 (assaulting public servant), he added.