JERUSALEM, ISRAEL - Israeli police said on Monday they had arrested a man suspected of slaughtering six members of the same family, including a newborn, because he was fired from the family restaurant they owned.

Demian Kerlik, 39, is suspected of stabbing to death the Oshrenko family in Rishon Lezion outside of Tel Aviv in October in a gruesome murder that shocked the country and was branded one of Israel's worst-ever.

The victims included Dmitry and Tatyana Oshrenko, their three-year-old daughter Revital and four-month-old son Netanel, and Dmitry's 56-year-old parents, Edward and Lyudmilla.

"He didn't slaughter them all at the same time, he simply waited in the flat for hours for all of them to come in one by one," police commander Avi Noiman told a crowded press conference on Monday.

After the killing, Kerlik set the apartment alight, police said. Kerlik immigrated five years ago to Israel from Russia, where he is allegedly wanted for robbery, police said.

Police believe that Kerlik carried out the killings because he was fired from his job at the restaurant owned by the Oshrenkos some two years ago, and this "developed into deep hatred over time."

Police central command chief major general Nissim Mor said Kerlik re-enacted the crime and that during the re-enactment he knelt in front of the crib in which he allegedly killed the four-month-old Netanel and asked for "forgiveness."

"There is no forgiveness for such a thing," Mor said. Police also arrested Kerlik's wife Natalia who admitted to planning to rob the family together with her husband.