Continuity mistake: When Russell Crowe walks towards Ben's diner in the outside shot, he has his bag over his shoulder, and it is stolen from the ground under his spot at the counter a moment later. When he enters the diner (the inside shot) he doesn't have his bag. So he couldn't have put it on the ground, and it couldn't have been stolen from there. (00:29:00)
Factual error: The building where Della goes to find the pizza boy is not a hospital. It is the HUD building, which contains only government offices - no one could be hospitalized there. (00:41:50)
Factual error: When Robert Bingham is shooting at Cal, an MPD (Washington, DC) squad car shows up. However, the scene is set in Crystal City in Arlington, Virginia, outside of MPD's jurisdiction. Arlington County Police would have responded instead. (01:13:05)
Continuity mistake: Crowe gives the girl reporter a necklace made of ballpoint pens. When Crowe leaves and she runs after him the necklace is gone. (01:47:45 - 01:48:45)
Factual error: A girl is shown walking in Adam Morgan, DC but is actually waiting to ride the DC Metro at Rosslyn Station in Virginia.
Factual error: When there is a killing in Georgetown, and Russell Crowe is responding he is shown driving through NW DC but then appears to be in SW DC where the murder victim's body is.
Answer: The assassin that Stephen hired to spy on Sonia found out and told Stephen. At some point off-screen, Stephen told Anne details about his affair with Sonia and accidentally told her that she was being paid to spy on and sleep with him for $26,000. Anne told Cal about the $26,000, and Cal realises that Stephen knows a lot more about Sonia's spying for Point Corp than he is letting on. If Stephen was completely innocent, there would be no way for him to know the amount was $26,000. Cal and his team of journalists never told Stephen the specific amount of money Sonia was getting.