Growing up in New York's Orthodox Community, Mordechai Dzikansky, a rabbi's son, did not envision his memoir would be titled Terrorist Cop.

Nor did Mr Dzikansky, 49, who now lives in Ra'anana, foresee that he would go from being a policeman who happens to be Jewish to the Jewish policeman of New York and, ultimately, to New York Police Department's ambassador to the Jewish state.

When Mr Dzikansky became a law enforcement officer in 1983, the NYPD was recruiting yarmulke-wearing officers, hoping Orthodox policemen would help serve that community.

Mr Dzikansky says he was offered work in the predominantly-Jewish Borough Park in Brooklyn, but he insisted on developing his reputation in the harshest neighbourhoods. His move paid off: "My colleagues thought 'he is one of 40,000 [NYPD policemen], not one of three [Orthodox cops]'."

The NYPD needed a detective to chase a suspected Israeli drug dealer in 1985, so Mr Dzikansky, "who'd fit into an Israeli restaurant and know what to order", took the lead in the case. When Rabbi Meir Kahane, an Israeli-American right-wing extremist, was assassinated in Manhattan in 1990, it was Mr Dzikansky, familiar with the political context, who immediately suggested the possibility of Islamist terrorism, which turned out to be correct.

"I had the pulse of both the Jewish and the Israeli community, because I was a card-carrying member," he says.

His Jewish beat evolved further, and from 1992-1993 he headed the Torah Task Force, which was investigating a series of thefts of Torah scrolls from synagogues throughout the city. For six months Mr Dzikansky worked exclusively on the case, and brought the epidemic to a halt. "It was a purely Jewish crime," he notes sadly, as the major felons turned out to be community insiders.

He was "at the pinnacle of his career" when September 11 changed everything and set him on a path that would lead him to Israel. Police Commissioner Raymond Kelly realised that New York could not rely exclusively on federal authorities for its security. The city had to take action, including by establishing connections with law enforcement agencies in other countries. What experience would be more valuable than Israel's, then suffering the second intifada?

New York dispatched Mr Dzikansky, who says he had always thought about immigrating to Israel but never planned it, to gain insights and information on what he calls "the urbane think-tank for terrorism in a Western country".

In Israel, Mr Dzikansky visited the sites of 21 suicide attacks in the immediate aftermath of the incidents, and passed the knowledge he gained on to colleagues in New York. After five years in Israel, Mr Dzikansky retired from the NYPD but decided to stay in the country.

He is now finishing his second book, a textbook on suicide-bombing.