What Did Jesus Write on the Ground?

Consider the following story:

Jesus went unto the mount of Olives. And early in the morning he came again into the temple, and all the people came unto him; and he sat down, and taught them. And the scribes and Pharisees brought unto him a woman taken in adultery; and when they had set her in the midst, They say unto him, Master, this woman was taken in adultery, in the very act. Now Moses in the law commanded us, that such should be stoned: but what sayest thou? This they said, tempting him, that they might have to accuse him. But Jesus stooped down, and with his finger wrote on the ground, as though he heard them not. So when they continued asking him, he lifted up himself, and said unto them, He that is without sin among you, let him first cast a stone at her. And again he stooped down, and wrote on the ground. And they which heard it, being convicted by their own conscience, went out one by one, beginning at the eldest, even unto the last: and Jesus was left alone, and the woman standing in the midst. When Jesus had lifted up himself, and saw none but the woman, he said unto her, Woman, where are those thine accusers? hath no man condemned thee? She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go, and sin no more.
- John 8:1-11 (KJV)

Although it's impossible to say what Jesus actually wrote on the ground, some people have suggested that the following verse explains what Jesus wrote on the ground.

O Lord, the hope of Israel, all that forsake thee shall be ashamed, and they that depart from me shall be written in the earth, because they have forsaken the Lord, the fountain of living waters.
- Jeremiah 17:13 (KJV)

The phrase "written in the earth" is the opposite of "written in the book (of life)".

That's very interesting, and it probably means Jesus wrote the names of all the scribes and Pharisees on the ground, and then said "He that is without sin among you, let him first cast a stone at her". Standing condemned, the scribes and Pharisees all left until Jesus was alone with the woman. Jesus then told the woman to "go, and sin no more".

Ellen White agrees with the above interpretation.

Giving no sign that He had heard their question, He stooped, and fixing His eyes upon the ground, began to write in the dust. Impatient at His delay and apparent indifference, the accusers drew nearer, urging the matter upon His attention. But as their eyes, following those of Jesus, fell upon the pavement at His feet, their countenances changed. There, traced before them, were the guilty secrets of their own lives. The people, looking on, saw the sudden change of expression, and pressed forward to discover what it was that they were regarding with such astonishment and shame.
- Ellen White, The Desire of Ages, p. 461

While researching this, I also learnt that under Jewish law, any matter (such as above) must be established by two or three witnesses.

One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established.
- Deuteronomy 19:15 (KJV)

To add weight to the credibility of the witnesses, they were also the ones that had to throw the first stone.

The hands of the witnesses shall be first upon him to put him to death, and afterward the hands of all the people. So thou shalt put the evil away from among you.
- Deuteronomy 17:7 (KJV)

So the witnesses played a key role in any trial, etc.