More than one week after Malaysia Airlines Flight 370 disappeared without a trace, authorities have extended their search - and refocused investigations on the pilot and co-pilot as possible suspects. 

Footage was released on Sunday evening showing the last known video of Captain Zaharie Ahmad Shah, and Co-Pilot Fariq Abdul Hamid of Flight 370 before boarding the plane - as both received pat-downs in a security check before taking off for Beijing. 

An investigation has already been launched against Shah, who has ties to Malaysia's Opposition leader, Anwar Ibrahim. Late Sunday, the New York Daily News noted that Opposition leader Ibrahim had been convicted of sodomy in a Malaysian criminal court and sentenced to five years in prison on March 7 - and that Flight 370 disappeared less than 24 hours later.

Malaysian authorities also backtracked on Monday when the missing flight's communications were disabled, switching from a confirmation that the system was disabled at 1:07 am to an admission that the facts remain unclear, according to the New York Times.

The Financial Express also revealed Monday that someone - who investigators believe to be Hamid - said the words "All right, good night," to ground controllers, shortly before the communications system went offline on the mystery flight.

The last signal from the Aircraft Communications Addressing and Reporting System (ACARS) was received 12 minutes before the co-pilot's final words.

In addition, the New Straits Times has reported several sightings from local witnesses that the plane was spotted flying as low 5,000 feet - possibly to avoid radar - across several countries, and could have flown as far as Central Asia or deep into the Indian Ocean. 

The disappearance of the plane with no trace has sparked a frantic search, which was extended on Monday to the Indian Ocean near Australia. Hijacking has been suspected given that, in addition to the plane turning around, it continued sending satellite signals for hours, indicating hundreds of miles or more of continued flight-time.

Suspicions deepened after Interpol found two Iranian nationals had boarded the plane on stolen Austrian and Italian passports, with Thai police reporting the passports were sold to both of them and the tickets booked for them by a third Iranian national.