"It is embarrassing because some of them concentrated on looting instead of raising alarms," said a police officer in the probe team who did not want to give his name.
"We're questioning all of them. Police officers, immigration staff, civilians who work in other areas and even taxi drivers," he added.
Security cameras caught some thieves in action, he said.
Kenyan paper Daily Nation said seven police officers could appear in court on Monday. The men were found with cash and alcohol on them, the paper said.
The cause of the fire that broke out at 5am at Jomo Kenyatta International Airport (JKIA) on Wednesday and blazed out of control for several hours has not yet been determined.
The airport's main arrivals hall was gutted in the blaze.
President Uhuru Kenyatta has ruled out terrorism.
But "those responsible for negligence will have to be punished", he warned on a visit to the airport on Friday.
The fire caused no casualties but paralysed the airport, which is the principal aviation hub for east Africa, on Wednesday. International and domestic flights were subsequently cancelled. – Sapa-AFP