Amritpal Singh has been on the run since last week.
Khalistani leader Amritpal Singh was in Haryana a day after fleeing the police in Punjab, the police sources have said. He stayed at the house of one of his associates on Sunday and left early the next morning, they added.
The associate, a woman named Baljeet Kaur, has been arrested, they said. Kaur told the police that Amritpal Singh came to her home in the Kurukshetra district with another aide, Papalpreet Singh, on a scooter.
The Punjab police have also arrested a man who was allegedly part of the private security setup of Amritpal Singh.
Tejinder Singh Gill, a resident of Mangewal village in the Khanna area of Ludhiana district, was tasked with the self-styled preacher's security.
"We have nabbed the woman, Baljeet Kaur, who harboured Amritpal and his associate Papalpreet Singh at her home in Shahabad on Sunday. The woman has been handed over to Punjab Police," Kurukshetra Superintendent of Police Surinder Singh Bhoria told news agency PTI.
Last month, Amritpal Singh and his supporters, some of them brandishing swords and guns, broke through barricades and barged into the Ajnala Police Station on the outskirts of the Amritsar city, and clashed with police for the release of one of the radical preacher's aides.
Last week, Punjab Police launched a crackdown against him and his outfit, 'Waris Punjab De'.
Amritpal Singh, however, gave the police a slip when his cavalcade was intercepted in the Jalandhar district.