An oil slick spotted in the sea between Malaysia and Vietnam that had been linked to the missing Malaysia Airlines Flight MH 370 was determined not to be from an aircraft, investigator said Monday. 

Investigator said authorities, who are investigating the identities of those boarded the flight with stolen passports, had reviewed video footage from check-in to departure and found that “all security protocols have been compiled with." 

Earlier on Monday, helicopters and ships spotted a yellow object in the water that looked like a life raft, but it turned out to be a moss-covered cap of a cable reel and not from the plane. 

Almost three full days have passed since the Boeing 777 with 239 people on board en route from Malaysia to Beijing lost contact. There is no confirmed wreckage. 

Authorities are looking into all possibilities. 

The video footage showed that the men with stolen passports were not of Asian appearance, said the investigator, Azharuddin Abdul Rahman, the head of Malaysian Department of Civil Aviation. He also said that the search area is being expanded.