Update, 7.30 p.m.: Sheih detained under Sedition Act. Malaysiakini has the full report here.
I have just received news that at about 4.00 p.m. Sheih was arrested at his home in Kota Bahru, Kelantan. It is yet unknown whether he had been detained under ISA or any other Act. His whereabout is yet unknown and attempts to reach him have failed. His blog is here.