Two men suspected of carrying out an antisemitic shooting of a US kosher supermarket are linked to the controversial Black Hebrew Israelite group, police have said.

The discovery of anti-Jewish social media posts by one of the suspects, confirmed by the New Jersey attorney general’s office, fuelled speculation that it was a targeted attack.

The rampage – at a kosher store in Jersey City, New Jersey on Tuesday – left the killers and three victims dead.

The following day, the FBI confirmed it had searched the Harlem headquarters of the Israelite Church of God in Jesus Christ, a movement linked to the anti-Jewish Black Hebrew Israelites.

The group, which is thought to have been active in the United States since the 1970s, preaches the belief that Ashkenazim are inauthentic Jews, and that black and Latino people are the descendants of the 12 tribes of Israel.

“The why and the ideology and the motivation — that's what we're investigating," New Jersey Attorney General Gurbir Grewal said Wednesday, adding that authorities are trying to determine whether anyone else was involved.

Steve Fulop, the Mayor of Jersey City, pronounced the attack a hate crime against Jews.

The attackers were identified as David N. Anderson, 47, and Francine Graham, 50.

The victims were 31-year-old Mindel Ferencz, the owner of the grocery store; Moshe Deutsch, a 24-year-old rabbinical student from Brooklyn; and store employee Douglas Miguel Rodriguez, 49.

Members of New York's Charedi Jewish community gathered on Wednesday night for funerals for Mrs Ferencz and Mr Deutsch.