Members of an armed police squad who the BBC has learned were ordered not to respond to Monday's mass shooting in Washington DC have yet to be contacted by the authorities.
Officials on a special investigative panel convened on Wednesday have yet to approach team members.
Gunman Aaron Alexis killed 12 people.
"No-one's talked to these officers since this happened," a Capitol Police source close to the incident told the BBC.
Members of the Capitol Police's highly trained Containment and Emergency Response Team (Cert) are typically debriefed "right away, at the very least the following day" following an incident, another Capitol Police source said.
But four days after Monday's shooting, the officers have yet to be questioned by the department or any member of a Capitol Police Board "Fact Review Team", which was convened on Wednesday to investigate the incident.
