An arson attack that left a man with severe burns has brought unwelcome scrutiny to a New York enclave of a strict Chasidic sect.

New Square - about 40 miles from New York City in Rockland County - is populated by Skver Chasidim, a group that originated in the Ukranian town of Skvyra. David Twersky has been its Grand Rabbi since his father died in 1968.

This insular village of about 7,000 people, where women do not drive and the sexes walk on opposite sides of the street, lives apart from the secular world - although its bloc vote gives New Square surprising political clout.

The village was thrust into the headlines on May 22, when Aron Rottenberg, 43, and his son, Jacob, confronted an intruder outside their home at around 4am. The man - who police say was Shaul Spitzer, 18, a home attendant for Rabbi Twersky - was trying to set fire to Mr Rottenberg's home.

In the confrontation, the attacker's incendiary device exploded, and Mr Rottenberg suffered third-degree burns across half of his body. Spitzer also suffered third-degree burns on his chest and arms and was charged with attempted murder, attempted arson and assault. He is now out on $300,000 bail and has returned to New Square.

Mr Rottenberg, who has had two skin-grafts, posted a video on failedmessiah.com from his hospital bed earlier this month in which he described the attack. He smelled a "terrible bad odour of gas", he said, before confronting the intruder. "I started yelling to my son that I was in flames," he said.

Last week Mr Rottenberg's lawyer, Michael Sussman, filed a lawsuit against Rabbi Twersky and Spitzer seeking $18 million - a figure Mr Sussman said was chosen because of the number's significance in Judaism.

The writ alleges that Spitzer "acted at the direction of the Grand Rabbi in whose home he then lived, to whom he gives absolute allegiance and without whose direction he would never have so acted".

It is an allegation rejected by Hank Sheinkopf, a well-connected political consultant who speaks for Rabbi Twersky. "The rabbi has been very public about condemning violence of all kinds," he says.

Mr Rottenberg, a plumber, says he had shocked New Square before the arson attack by turning his back on the rabbi's synagogue. He prayed instead at a nearby nursing home that houses a small synagogue for residents' use.

Before the attack, according to the lawsuit, there were other acts of hostility. Mr Rottenberg's daughter, Tzurity, was expelled from the local religious school, her notebooks left scattered on the family front porch. And there were threatening phone calls and stones tossed at Mr Rottenberg's car windows.

Local police and the FBI are examining the incidents for possible violations of hate-crime laws.

Shulem Deen, 36, who grew up in New Square but left the community seven years ago, describes Mr Rottenberg as "an outspoken personality" and "an amazing conversationalist". He said the community finds Mr Rottenberg's rejection of Twersky's shul "deeply objectionable" and an insult to the rabbi.

But Mr Deen, despite his own strong reservations about Rabbi Twersky's lavish lifestyle - he says the rabbi rides around in a Cadillac and dines off silver platters - does not think Spitzer was ordered to attack Mr Rottenberg. "I think it's very likely he acted at the behest of his peers. He probably wanted to be a hero," he alleged.

The rabbi has not contacted the Rottenbergs, but a few days after the attack spoke about his hatred of violence.