Whom do men say that I am?—St. Matthew.
Whom think ye that I am?—Acts of the Apostles.
Who should be written in both cases because the word is not in the objective governed by say or think, but in the nominative dependent on the verb am.
"Who should I meet at the coffee house t'other night, but my old friend?"—Steele.
"It is another pattern of this answerer's fair dealing, to give us hints that the author is dead, and yet lay the suspicion upon somebody, I know not who, in the country."—Swift's Tale of a Tub.
"My son is going to be married to I don't know who." —Goldsmith's Good-natured Man.
The nominative who in the above examples should be the objective whom.
The plural nominative ye of the pronoun thou is very often used for the objective you, as in the following:
"His wrath which will one day destroy ye both." —Milton.
"The more shame for ye; holy men I thought ye."—Shakespeare.