For Bible and Interpretation is worth a look.
The body was laid in a shallow pit or on a shelf for the first year, during which the flesh decayed, while the soul underwent the purifying process. The relatives laid tree branches on the corpse, and it was also customary to leave perfume tools in the tomb or pour perfume directly on the corpse. A year after the burial, the relatives returned to the tomb, collected the bones and put them in stone boxes: ossuaries. It was a celebration: the relatives were assured that the deceased finally arrived at his proper place, under the Seat of Honor and eternal, pure life. Now they collected the bones to the ossuary, and put the ossuary in a niche, carved into the tomb wall.