Only one person from the Special Service Bureau came down. He was wearing a suit, indicating he wasn't from the uniformed group, but his orders seemed to be the most authoritative at the moment.
Another person, shouting for the police to stop Gao Yi and the others, was from the FBI, but his words didn't have much effect, because Buck, also from the FBI, was waving credentials, asking the police to let them pass.
Joelson said that CIA people would arrive soon, but they hadn't appeared yet. However, Gao Yi thought that the person from the Special Service Bureau was likely brought by Joelson as an ally, meant to cover his retreat.
The reason is simple: the CIA lacks law enforcement authority on US soil, but the Special Service Bureau does, and with very high authority. When confronted with the FBI, it's the FBI that has to back down.
The most bewildered ones now are the police.
