CNN crime and justice producer David Shortell said Friday that the network set up a camera crew outside the home of longtime political operative Roger Stone after “noticing unusual grand jury activity” in connection to special counsel Robert Mueller’s Russia investigation the day before.

CNN producer @davidgshortell describes the moment Roger Stone was taken into custody by the FBI. The longtime Donald Trump associate has been indicted by a grand jury on charges brought by special counsel Robert Mueller https://t.co/wUJEIkKDTw pic.twitter.com/AJ3JWWSHs3 — CNN (@CNN) January 25, 2019

A partial transcript is as follows:

ALISYN CAMEROTA: Tell us everything that transpired this morning. DAVID SHORTELL (pictured): Alisyn, an extraordinary morning. We were here since 5:00 a.m. waiting for whatever was going to happen. It was dark. 6:00 a.m., just after the hour, about a half dozen police vehicles with sirens, but no sounds, pull in front of this Fort Lauderdale home, where Roger Stone was presumably asleep. The lights were off in the house. About a dozen officers, FBI agents wearing tactical vests and with large weapons fanned out across his front lawn. One went up to the house and rapped on the door, shined a flashlight inside, said “FBI, open the door.” Moments later, as you heard in the video, it say “FBI warrant,” that’s what the agent said. We then saw a light go on the second floor and moments later, there was Roger Stone in the doorway. … CAMEROTA: What’s so fascinating is that we’ve talked to his attorney, the attorney didn’t know it was coming. Clearly, Roger Stone didn’t know this was coming. You were staked out at his house, you didn’t know that this was coming. Why were you there in position? SHORTELL: Alisyn, it’s a reporter’s instinct. The whole Russia team thought maybe something was happening. There was unusual grand jury activity in Washington, D.C. yesterday. The grand jury, Robert Mueller’s grand jury, typically meets on Friday — yesterday, a Thursday, there was grand jury activity. We also had some other signs that maybe something was going on this angle, the Roger Stone angle. So we showed up at his house this morning, we were the only ones there, and, lo and behold, the FBI agents did come and arrest him.

Reacting to the arrest, President Donald Trump called the Mueller probe the “Greatest Witch Hunt” in U.S. history and asked, who had “alerted” CNN to camp outside Stone’s home. CNN’s official communications Twitter handle replied that the network’s “ability to capture the arrest of Roger Stone was the result of determined reporting and interpreting clues revealed in the course of events.”

“That’s called journalism,” they added