Mr Collins and his partner Alana Madill were killed when the car they were in was hit by a bus on a motorway near Beziers, in southern France, on early on Friday morning (local time).
The couple's daughter, Ayla, suffered serious injuries in the crash, and remains in a serious condition in a Montpellier hospital in France.
In a statement, Yvon Clavet, who is leading the investigation into the cause of the accident, said "the state of the health of Ayla still remains worrying".
Ms Clavet said further analysis and investigations were being carried out, most notably on the car in which the couple and their baby daughter were travelling in.
"In order to pinpoint the exact circumstances ... an expert examination of the vehicles has been ordered," Ms Clavet said.
Meanwhile, Ms Madill's parents have travelled from Canada to the hospital to be with their granddaughter.
Friends and family of the couple, including Ms Madill's sister, are already by the baby's side, French newspaper L'Independent said.
An account for baby Ayla on fundraising site Givealittle has also exceeded its target of $25,000.
Last night, more than 530 people had donated and $28,399 had been pledged.
