The mourning over the dead Christ is generally represented as taking place immediately after his body was brought down from the Cross. There is no reference to it in the Bible.
The body of Christ is shown laid out on the ground with the Virgin Mary, John the Evangelist and Mary Magdalene grouped around it, mourning. The Magdalen is usually embracing Christ's feet, washing them with her tears. The Virgin sometimes holds his head. Nicodemus and Joseph of Arimathaea are also frequently included.