Can free will exist?

I have always considered that arguments that free will is a myth to be incorrect. But I was reasoning backward, whereas the anti-free willers were reasoning forward:

 Many scientists say that the American physiologist Benjamin Libet demonstrated in the 1980s that we have no free will. It was already known that electrical activity builds up in a person’s brain before she, for example, moves her hand; Libet showed that this buildup occurs before the person consciously makes a decision to move. The conscious experience of deciding to act, which we usually associate with free will, appears to be an add-on, a post hoc reconstruction of events that occurs after the brain has already set the act in motion.

Now it appears that I was right and there is a reasoning-forward way to explain why:

Based on these results, the researchers pieced together a biography of the boy’s brain.

When he was just an embryonic ball in the womb, five lineages of cells had emerged, each with a distinct set of mutations. Cells from those lineages migrated in different directions, eventually helping to produce different organs — including the brain.

The cells that became the brain turned into neurons, but they did not all belong to the same family. Different lineages merged together. In essence, the boy’s brain was made of millions of mosaic clusters, each composed of tiny cellular cousins.

It’s hard to say what these mosaic neurons mean to our lives — what it means for each of us to have witches’ broom growing in our skulls. “We don’t know yet whether they have any effect on shaping our abilities or challenges,” said Dr. Walsh.

However, the author of this report is Carl Zimmer who I do not entirely trust. But I don't see any suspicious claims in this report in The New York Times.

(There is another reasoning-forward way to get to a similar result, arguing from uncertainty but it is a weaker argument based on subatomic events which may not really affect out atomic brains.)