KUALA LUMPUR, April 1 — Voice stress analysis of the final radio transmission from Malaysia Airlines MH370 gave no indication that the pilot who made it was under duress, according to a report by China-based CCTV.

In a crossover telecast to Beijing yesterday, news anchor James Chau included the information as part of a revelation that the last words spoken — presumably by co-pilot Fariq Ab Hamid — were “Good night, Malaysian 370” rather than the previously circulated “Alright, good night.”

“What we do know is these (Good night, Malaysian 370) are the correct words, we do know that voice analysis shows that the voice that spoke those words at that time was also not under any obvious signs of duress or pressure,” Chau said.

The anchor on the state-owned English language news channel said the information detracted from the likelihood that either or both pilots on board the plane that went missing on March 8 with 239 people on board had acted with criminal intent.

The CCTV report was the latest contradiction to emerge from investigations into the missing Boeing 777-200ER that have been riddled with inconsistencies, but Chau was quick to note that this new development was positive.

He said this showed Malaysia was committed to revisiting previously known “facts” about the case, in light of the plane’s continued disappearance.

But the two new pieces of information also deepened the “unprecedented” mystery that has left both investigators and searchers racing to locate the plane, baffled.

On March 15, Malaysia announced that MH370 was deliberately taken off course on the day it disappeared, and that investigations were now focused on the 12 crew members and 227 passengers on board.

Attention has fallen most on the two pilots — captain Zaharie Ahmad Shah and Fariq — as investigators insist the circumstances of the plane’s diversion required piloting and avionics expertise.

Investigators also said all 227 passengers were cleared by intelligence agencies from all countries whose nationals were on board, save for Russia

While the two pilots have borne the brunt of public suspicion, investigators have not found any evidence to suggest foul play on the part of either man or anyone else on board, for that matter.

Search effort is now concentrated in a section of the Indian Ocean some 2,000km west of Perth in Western Australia where satellite images have spotted pieces of debris possibly from MH370, although recovery could still take years even if it is established that the plane went down at the location.

Time is running out, however, to locate the missing wreckage using the locator beacons on the two so-called “black boxes” — a flight data recorder and cockpit voice recorder — before their 30-day battery life expires.

With the US Navy’s towed pinger locator, dubbed the “black box finder”, only expected to arrive at the search site 2,000km west of Perth in Western Australia on April 3, searchers may have as few as five precious days to find the two recorders before they fall silent.

Investigations are now completely resting on the discovery of the two crucial pieces of equipment, as lack of known facts in the plane’s disappearance has prevented investigators from credibly presenting a plausible scenario.