kept his belief a secret, even denying his relationship to Baha'u'llah

Mirza Rida-Quli Hakim Nuri (1242/1846-1312/1894, see fig. 91), the half-brother of Baha'u'llah and a prominent physician in Tehran, believed in Baha'u'llah but kept his belief a secret, even denying his relationship to Baha'u'llah on one occasion in the presence of the shah. When Baha'u'llah had been released from the Siyah Chal in 1853, it was to Rida-Quli's house that he came to recover prior to setting out for Baghdad...

(The Baha'i Communities of Iran, Moojan Momen, p. 318)