A picture taken on July 31, 2015 shows a man holding a picture of 18-month-old Palestinian toddler

Israeli police said Tuesday they have arrested four Jewish men suspected of being among gun-waving extremists filmed celebrating the murder of a Palestinian toddler in a firebombing.

They were shown in a wedding video, broadcast last week by an Israeli news channel, which spread online and drew strong condemnation from Israeli politicians including Prime Minister Benjamin Netanyahu.

"Four people have been arrested until now," police spokesman Micky Rosenfeld told AFP.

"An investigation was opened last week and, during this week, four people were arrested and are scheduled to appear tomorrow morning in front of a Jerusalem court" for a remand hearing, he said.

"That's in connection with the weapons that were at the wedding and other things."

He gave no further details, but Israeli public radio said among those arrested were the groom, a soldier who lent his assault rifle to another reveller and a former activist of the outlawed Kach extremist movement allegedly shown brandishing a weapon and calling for revenge against Arabs.

The video showed guests dancing with guns, knives and at least one unlit Molotov cocktail, while slashing a picture of the toddler killed in the firebombing of his home that also fatally wounded his parents and was blamed on Jewish extremists.

Media reported that the groom had previously been questioned over acts of "Jewish terrorism" while other guests were friends or relatives of suspects arrested over the July attack.

Netanyahu called the video "shocking" and said it showed "the true face of a group that constitutes a danger to Israeli society and to the security of Israel".

In recent weeks, Israel has arrested a number of suspected Jewish extremists over the July 31 incident in the West Bank village of Duma. So far, no one has been charged.

One of them, an 18-year-old settler, was put under house arrest Tuesday after weeks in the custody of the Shin Bet domestic security service, media reported.
He was ordered released on Monday, when prosecutors admitted that did not intend to charge him over the Duma killings, but over a 2013 assault on a Palestinian.

He was held a further day while the prosecution appealed against his release.

The fired killed 18-month-old Ali Saad Dawabsha, while his parents later died from severe burns. Ali's four-year-old brother was the sole survivor from the immediate family.

A Star of David and the words "revenge" and "long live the Messiah" were spray-painted on a wall near the family's small house.

Palestinians have often highlighted the lack of progress in the Duma case as one of the causes of a wave of knife, gun and car-ramming attacks targeting Israelis that began on October 1.
Source: AFP