Hasan Niku accused ‘Abdu’l-Baha of excessive worldly ambition and desire for money.

Hasan Niku was a leading Iranian Baha’i missionary who, after leaving the Baha’i faith, published a book explaining why he became disillusioned with the movement. Among other things, he accused ‘Abdu’l-Baha of excessive worldly ambition and desire for money, and criticized him for writing flattering epistles to wealthy and powerful people whom he hoped to win as disciples.

(A Lost History of the Baha’i Faith, by Shua'u'llah Behai)