CNN claims to have people at the Grand Jury, and a team of investigators, and deduced that Stone was the target. The Grand Jury usually meets Fridays, and for some reason they met that Thursday so CNN claims they knew something was up.
FWIW, even Roger Stone said he expected to be indicted. So at least the CNN story ‘adds up’. But other aspects contradict - why did they need so many heavily armed agents, and if they thought they needed that much firepower to shoot at a 66 year old man and his deaf wife, why did they let the CNN reporter get so close?
No, still doesn’t add up. Just because they knew something might happen, unless someone leaked, they would have had no idea it would take place at the time and place that it did. Also, that type of information is not the subject of Grand Jury deliberations or testimony. Finally, how did CNN know it was going to be a raid and not an agreed to time and place for Stone to turn himself in. No, it was a leak done to make maximum publicity to tarnish Trump by innuendo.