Death threat in envelope containing a bullet sent to Israel PM's eldest son

April 28 (UPI) -- A death threat was sent to Israeli Prime Minister Naftali's Bennett's eldest son in an envelope containing a bullet, local sources said Thursday.

The letter was the second death threat sent to the Bennett family this week in an envelope containing a bullet.

This time the letter threatened his eldest son, Yoni Bennett, 17, specifically, Walla reported.

"It's so sad that things like this happen because of incitement," the prime minister's eldest son said on social media, Walla reported.

An investigation opened after the first death threat was sent to Bennett's family, police said, and the Prime Minister's Office has increased security of the family's protection unit.

"Political conflict, no matter how profound, should not reach violence, bullying and death threats," Bennett tweeted, The Jerusalem Post reported. "We need to do everything, as leaders and citizens whose future and the future of their children are in this country, so that such phenomena simply do not happen."

The Israel Security Agency, known as the Shin Bet, is investigating the death threats along with the Lahav 433 unit of the Israel Police.

Israel Foreign Affairs Minister Yair Lapid condemned the first letter on social media, similarly citing incitement as a cause.

"The letter threatening the prime minister's life is a sad and dangerous reminder of where incitement could lead," Lapid tweeted. "We will continue to fight the hate discourse on the street, in networks, everywhere. They will not scare us. The extremists will not defeat the sane majority."