Had he switched sides to cooperate with the United States government?
On Tuesday, Mr. Zarrab gave a stunning answer, appearing as the government’s star witness in the trial of Mr. Attila, the Turkish banker who had been charged with him.
Through three days of often-compelling testimony, Mr. Zarrab has appeared composed, has maintained a respectful tone and has rarely looked uncomfortable answering questions. His testimony about how he had carried out the scheme, working with bankers and a government minister, sent political tremors through Turkey.
Hints emerged about why Turkey’s president was so interested.
Ever since Mr. Zarrab’s arrest in March 2016, Turkey’s president, Recep Tayyip Erdogan, has repeatedly condemned the prosecution and seemingly tried everything to have the case dismissed.
Mr. Erdogan claimed there were “malicious” intentions behind the prosecution, and he raised the case with American officials, including Mr. Trump, in a phone call in September.
“We have to seek justice, for he is our citizen,” Mr. Erdogan said of Mr. Zarrab more than a year ago.
But in his testimony this past week, Mr. Zarrab all but implicated Mr. Erdogan in the alleged scheme. He testified that Zafer Caglayan, then the economy minister, had told him in 2012 that Mr. Erdogan, who was prime minister at the time, had personally ordered that two Turkish banks be allowed to participate in the sanctions-busting activity.
Mr. Zarrab also said he had paid Mr. Caglayan tens of millions of dollars in bribes. Mr. Caglayan is one of the seven defendants who remain at large.
Turkey was abuzz.
Turkey has been gripped by the trial, with its cast of rich and powerful characters and its enormous sums: billions of dollars in Iranian oil money and bribes in the tens of millions of dollars, allegedly paid to the former economy minister.
The Turkish government tried to head off negative news coverage, denouncing the trial in the days before it began as a plot against the government and against Turkey itself.
Justice Minister Abdulhamit Gul said the evidence had been fabricated by followers of the cleric Fethullah Gulen — who was accused of fomenting last year’s failed coup against Mr. Erdogan — and that a 2013 Turkish police investigation into the matter had been dismissed for that reason. Mr. Gulen lives in self-imposed exile in Pennsylvania.
In Turkey’s increasingly authoritarian climate — a state of emergency has…