Democrat Fred Li Wah-ming wrote to Chief Executive Tung Chee-hwa yesterday urging him to find out why his mainland home return permit was confiscated on Saturday. In the letter, Mr Li wrote that his permit was taken from him at Lok Ma Chau border checkpoint after he was detained by mainland authorities for 45 minutes. He had intended to go on a lychee-picking tour in Dongguan with relatives. A plain-clothes mainland official told him that he had 'endangered national security and harmed the interests of the state', Mr Li said. Mr Li said it was inappropriate for a mainland law-enforcement agent to make such a serious allegation against him without any concrete evidence or explanation. He urged Mr Tung to ask mainland authorities to provide evidence to substantiate what he described as a groundless accusation. 'Should there be no reasonable evidence, I would like to request you to follow the matter up with the mainland authorities and to reissue a home return permit for me as soon as possible,' he said. Mr Li first had his home return permit confiscated in 1999.