Israel has charged four Jewish extremists suspected over a July arson attack on a Palestinian home that killed a toddler and his parents.
The case has been unsolved for months and helped fuel the current wave of Israeli-Palestinian violence.
The long-awaited indictment follows months of investigations into a web of Jewish extremists operating in the West Bank.
The indictment named Amiram Ben-Uliel, 21, as the main suspect in the attack. A minor was charged as an accessory. Yinon Reuveni, 20, and another minor were charged for other violence against Palestinians.
The arson attack in the West Bank village of Duma killed 18-month-old Ali Dawabsheh, while his mother, Riham, and father, Saad, later died of their wounds. Ali's four-year-old brother Ahmad survived.
The firebombing, carried out under cover of darkness while the family slept, sparked soul-searching among Israelis rattled by the horrific attack.
It was condemned across the Israeli political spectrum and Prime Minister Benjamin Netanyahu pledged "zero tolerance" in the fight to bring the assailants to justice. Israel has authorised a series of steps, including administrative detention, to try and crack the case.
But for months, Palestinians watched angrily as the case remained unsolved, intensifying a feeling of skewed justice in the occupied territory, where suspected Palestinian militants are prosecuted under a separate system of military law that gives them few rights. The arson also touched on Palestinian fears of extremist Jewish settlers, who have attacked Palestinian property with impunity.
Palestinians cite the Duma incident as a factor in the three-month wave of attacks and clashes affectling the region, saying they are frustrated by years of unchecked settler violence.
Israel's Shin Bet security service says the suspects admitted to carrying out the attack, saying it was in retaliation for the killing of an Israeli a month earlier. It said all the suspects were part of a group of extremists that had carried out a series of attacks over the years and whose goal was to undermine the state.
Jewish extremists have for years vandalised or set fire to Palestinian property, as well as mosques, churches, the offices of dovish Israeli groups and even Israeli military bases. The so-called "price tag" attacks seek to exact a cost for Israeli steps seen as favouring the Palestinians.
The extremists are part of the so-called "hilltop youth," a leaderless group of young people who set up unauthorised outposts, usually clusters of trailers, on West Bank hilltops - land the Palestinians claim for their hoped-for state.
A lawyer for one of the suspects says his client gave a forced confession after interrogators deprived him of sleep and tied him upside down by his feet.
The indictment said Ben-Uliel admitted to spraying graffiti on the Dawabsheh family home and then tossing a firebomb through a bedroom window before fleeing the scene. Ben-Uliel's parents said they believe in his innocence and that he was tortured during interrogation.
Nasser Dawabsheh, Saad's brother, said the indictments were not enough.
"It's clear the Israeli institutions are not serious," he said. "It's clear there was an organisation behind this crime, even the media knows that. And the government was not serious in preventing it and is not serious in pursuing the killers."