Brian and Grace Johnston, 19-year-old former student Caitlin Dickson and driver Christopher Mmata died in the crash.
Mr Crosbie said their bodies were in Nairobi before being brought back to New Zealand.
Funerals would be held at the college in due course.
Mr Crosbie said the four people in the group who did not need medical treatment could not travel on the medivac planes to Nairobi with the others.
They would instead travel on a commercial flight tomorrow, along with diplomatic staff who had now arrived in Kisumu.
Bethlehem College deputy principal Stuart Manners was on his way to Nairobi, while a House of Travel representative had arrived in Nairobi to help with travel plans.
Those in the group who were well enough to fly would return to New Zealand as soon as possible.
A Ministry of Foreign Affairs and Trade (MFAT) spokeswoman this morning said two New Zealand diplomats had arrived in Kisumu to provide ongoing support and advice to the college group.
Deputy High Commissioner Georgina Roberts had travelled from the High Commission in Pretoria, South Africa, while Consul Barbara Welton had flown to Kenya from the embassy in Cairo, Egypt.
The spokeswoman said the process of repatriating the three bodies was underway, but a timeline for their return to New Zealand was still to be confirmed.
MFAT declined a request for an interview with its diplomatic staff in Kisumu, saying their priority was on providing support.
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