when Baha'u'llah and his son and successor Abbas Effendi died, the Sunni clergy conducted their funeral services.

The Muslims of Akka were all Sunnites, and were quite intolerant of heretics such as the Baha'is. Therefore, in order to avoid trouble, Baha'u'llah and his followers took great pains to conceal their real beliefs, as they had done previously in Iran, Baghdad, and Edirne, and to profess and practice in public the faith of Islam. Accordingly, they went regularly to the Muslim mosques and recited the prayers after the manner of the Sunnites. They also kept the Muslim month of fasting. So successful were they in this effort that when Baha'u'llah and his son and successor Abbas Effendi died, the Sunnite clergy conducted their funeral services. This they would never have done had they realized that Baha'u'llah claimed to be a Manifestation of God, greater than Muhammad.

(The Baha'i Faith, William McElwee Miller, p 121-122)