Story highlights WSJ: Police have recorded 170 statements and will interview more people

Search area for new day shifts eastward

Malaysian authorities revise language used in last radio communications

Wednesday is the 26th day authorities have been searching for Flight 370

The investigation into Malaysia Airlines Flight 370 is now classified as a criminal investigation, The Wall Street Journal reported, citing the Malaysian police chief.

Inspector General of Police Khalid Abu Bakar said authorities have already recorded more than 170 statements and will interview more people for the Flight 370 probe, the Journal said.

But Bakar cautioned that what happened with Flight 370 might still be unknown after the investigation.

He added that the investigation into the flight simulator in the pilot's house is still inconclusive. Authorities are awaiting an expert's report on the simulator, he said.

After three and a half weeks, the search for the missing plane has come down to this: a lot of floating rubbish, hundreds of heartbroken relatives and, now, quibbling over words all acknowledge offer no clues into what happened to the doomed plane.

Malaysian authorities on Tuesday released the transcript of radio chatter between air traffic controllers and the plane in the hour or so before it vanished while flying from Kuala Lumpur, Malaysia, to Beijing on March 8 with 239 people on board.

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The transcript shows the last voice transmission from the doomed plane was "Good night Malaysian three-seven-zero" -- not the "All right, good night" transmission authorities had previously used.

The comments are "exactly what you'd expect" in a cockpit, airline safety expert John Gadzinski told CNN's "The Lead." Still, even if this new transcript offers no clues about the plane's mysterious disappearance, the discrepancy has provided fresh fodder for critics of Malaysia's handling of the investigation.

That authorities gave one version and let it stand uncorrected for weeks undermines confidence in the investigation, air accident investigation experts told CNN.

"High criticism is in order at this point," said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation.

And Michael Goldfarb, a former chief of staff at the Federal Aviation Administration, added that people following the investigation "haven't had a straight, clear word that we can have a lot of fidelity in."

"We have the tragedy of the crash, we have the tragedy of an investigation gone awry and then we have questions about where we go from here," he said.

Malaysian officials have defended their work, with acting Transport Minister Hishammuddin Hussein recently saying, "History will judge us well."

Regardless of one's assessment of Malaysia's response, that doesn't change the immense challenge it faces -- especially given the few apparent details on altitude, speed and, of course, location.

"They are looking in a vast area in very deep waters, ... and we really have no idea where it went in," Bill Schofield, an Australian scientist who helped create flight data recorders that could be key in determining what happened, told CNN. "... A needle in a haystack would be much easier to find."

Search 'could drag on'

After refocusing their search Friday to a new patch of Indian Ocean hundreds of miles from where they had been looking, authorities still haven't found anything definitively linked to Flight 370.

Ten aircraft and nine ships crisscrossed a 46,000-square-mile (120,000-square-kilometer) search zone on Tuesday. With so many planes in the skies over the search zone, Australia sent an airborne air traffic control plane to guard against accidents.

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Photos: The search for MH370 Photos: The search for MH370 Two years after Malaysia Airlines Flight 370 went missing, a relative of one of the passengers burns incense in Beijing on March 8, 2016. Flight 370 vanished on March 8, 2014, as it flew from Kuala Lumpur, Malaysia, to Beijing. There were 239 people on board. Hide Caption 1 of 43 Photos: The search for MH370 On July 29, police carry a piece of debris on Reunion Island, a French territory in the Indian Ocean. A week later, authorities confirmed that the debris was from the missing flight. Hide Caption 2 of 43 Photos: The search for MH370 Staff members with the Australian Transport Safety Bureau examine a piece of aircraft debris at their laboratory in Canberra, Australia, on July 20. The flap was found in June by residents on Pemba Island off the coast of Tanzania, and officials had said it was highly likely to have come from Flight 370. Experts at the Australian Transport Safety Bureau, which is heading up the search for the plane, confirmed that the part was indeed from the missing aircraft. Hide Caption 3 of 43 Photos: The search for MH370 In late February, American tourist Blaine Gibson found a piece of plane debris off Mozambique, a discovery that renewed hope of solving the mystery of the missing flight. The piece measured 35 inches by 22 inches. A U.S. official said it was likely the wreckage came from a Boeing 777, which MH370 was. Hide Caption 4 of 43 Photos: The search for MH370 Relatives of the flight's passengers console each other outside the Malaysia Airlines office in Subang, Malaysia, on February 12, 2015. Protesters had demanded that the airline withdraw the statement that all 239 people aboard the plane were dead. Hide Caption 5 of 43 Photos: The search for MH370 A police officer watches a couple cry outside the airline's office building in Beijing after officials refused to meet with them on June 11, 2014. The couple's son was on the plane. Hide Caption 6 of 43 Photos: The search for MH370 Members of the media scramble to speak with Azharuddin Abdul Rahman, director general of Malaysia's Civil Aviation Department, at a hotel in Kuala Lumpur, Malaysia, on May 27, 2014. Data from communications between satellites and the missing flight was released the day before, more than two months after relatives of passengers said they requested it be made public. Hide Caption 7 of 43 Photos: The search for MH370 Operators aboard the Australian ship Ocean Shield move Bluefin-21, the U.S. Navy's autonomous underwater vehicle, into position to search for the jet on April 14, 2014. Hide Caption 8 of 43 Photos: The search for MH370 A member of the Royal New Zealand Air Force looks out of a window while searching for debris off the coast of western Australia on April 13, 2014. Hide Caption 9 of 43 Photos: The search for MH370 The HMS Echo, a vessel with the British Roya; Navy, moves through the waters of the southern Indian Ocean on April 12, 2014. Hide Caption 10 of 43 Photos: The search for MH370 A Royal Australian Air Force AP-3C Orion, on a mission to drop sonar buoys to assist in the search, flies past the Australian vessel Ocean Shield on April 9, 2014. Hide Caption 11 of 43 Photos: The search for MH370 A relative of a missing passenger cries at a vigil in Beijing on April 8, 2014. Hide Caption 12 of 43 Photos: The search for MH370 Australian Defense Force divers scan the water for debris in the southern Indian Ocean on April 7, 2014. Hide Caption 13 of 43 Photos: The search for MH370 A towed pinger locator is readied to be deployed off the deck of the Australian vessel Ocean Shield on April 7, 2014. Hide Caption 14 of 43 Photos: The search for MH370 A member of the Royal New Zealand Air Force looks at a flare in the Indian Ocean during search operations on April 4, 2014. Hide Caption 15 of 43 Photos: The search for MH370 On March 30, 2014, a woman in Kuala Lumpur prepares for an event in honor of those aboard Flight 370. Hide Caption 16 of 43 Photos: The search for MH370 The sole representative for the families of Flight 370 passengers leaves a conference at a Beijing hotel on March 28, 2014, after other relatives left en masse to protest the Malaysian government's response to their questions. Hide Caption 17 of 43 Photos: The search for MH370 A member of the Royal Australian Air Force is silhouetted against the southern Indian Ocean during the search for the missing jet on March 27, 2014. Hide Caption 18 of 43 Photos: The search for MH370 Flight Lt. Jayson Nichols looks at a map aboard a Royal Australian Air Force aircraft during a search on March 27, 2014. Hide Caption 19 of 43 Photos: The search for MH370 People in Kuala Lumpur light candles during a ceremony held for the missing flight's passengers on March 27, 2014. Hide Caption 20 of 43 Photos: The search for MH370 Malaysian Prime Minister Najib Razak, center, delivers a statement about the flight on March 24, 2014. Razak's announcement came after the airline sent a text message to relatives saying it "deeply regrets that we have to assume beyond any reasonable doubt that MH 370 has been lost and that none of those onboard survived." Hide Caption 21 of 43 Photos: The search for MH370 Grieving relatives of missing passengers leave a hotel in Beijing on March 24, 2014. Hide Caption 22 of 43 Photos: The search for MH370 A passenger views a weather map in the departures terminal of Kuala Lumpur International Airport on March 22, 2014. Hide Caption 23 of 43 Photos: The search for MH370 A Chinese satellite captured this image, released on March 22, 2014, of a floating object in the Indian Ocean, according to China's State Administration of Science. It was a possible lead in the search for the missing plane. Surveillance planes were looking for two objects spotted by satellite imagery in remote, treacherous waters more than 1,400 miles from the west coast of Australia. Hide Caption 24 of 43 Photos: The search for MH370 Satellite imagery provided by the Australian Maritime Safety Authority on March 20, 2014, showed debris in the southern Indian Ocean that could have been from Flight 370. The announcement by Australian officials raised hopes of a breakthrough in the frustrating search. Hide Caption 25 of 43 Photos: The search for MH370 Another satellite shot provided by the Australian Maritime Safety Authority shows possible debris from the flight. Hide Caption 26 of 43 Photos: The search for MH370 A distraught relative of a missing passenger breaks down while talking to reporters at Kuala Lumpur International Airport on March 19, 2014. Hide Caption 27 of 43 Photos: The search for MH370 On March 18, 2014, a relative of a missing passenger tells reporters in Beijing about a hunger strike to protest authorities' handling of information about the missing jet. Hide Caption 28 of 43 Photos: The search for MH370 U.S. Navy crew members assist in search-and-rescue operations in the Indian Ocean on March 16, 2014. Hide Caption 29 of 43 Photos: The search for MH370 Members of the Chinese navy continue search operations on March 13, 2014. After starting in the sea between Malaysia and Vietnam, the plane's last confirmed location, search efforts expanded west into the Indian Ocean. Hide Caption 30 of 43 Photos: The search for MH370 A Vietnamese military official looks out an aircraft window during search operations March 13, 2014. Hide Caption 31 of 43 Photos: The search for MH370 Malaysian air force members look for debris near Kuala Lumpur on March 13, 2014. Hide Caption 32 of 43 Photos: The search for MH370 Relatives of missing passengers wait for the latest news at a hotel in Beijing on March 12, 2014. Hide Caption 33 of 43 Photos: The search for MH370 A member of the Vietnamese air force checks a map while searching for the missing plane on March 11, 2014. Hide Caption 34 of 43 Photos: The search for MH370 A Vietnamese air force plane found traces of oil that authorities had suspected to be from the missing Malaysia Airlines plane, the Vietnamese government online newspaper reported on March 8, 2014. However, a sample from the slick showed it was bunker oil, typically used to power large cargo ships, Malaysia's state news agency, Bernama, reported on March 10, 2014. Hide Caption 35 of 43 Photos: The search for MH370 A U.S. Navy Seahawk helicopter lands aboard the USS Pinckney to change crews on March 9, 2014, before returning to search for the missing plane in the Gulf of Thailand. Hide Caption 36 of 43 Photos: The search for MH370 Buddhist monks at Kuala Lumpur International Airport offer a special prayer for the missing passengers on March 9, 2014. Hide Caption 37 of 43 Photos: The search for MH370 Members of a Chinese emergency response team board a rescue vessel at the port of Sanya in China's Hainan province on March 9, 2014. Hide Caption 38 of 43 Photos: The search for MH370 The rescue vessel sets out from Sanya in the South China Sea on March 9, 2014. Hide Caption 39 of 43 Photos: The search for MH370 Malaysian Prime Minister Najib Razak, center, arrives to meet family members of missing passengers at the reception center at Kuala Lumpur International Airport on March 8, 2014. Hide Caption 40 of 43 Photos: The search for MH370 A relative of two missing passengers reacts at their home in Kuala Lumpur on March 8, 2014. Hide Caption 41 of 43 Photos: The search for MH370 Chinese police at the Beijing airport stand beside the arrival board showing delayed Flight 370 in red on March 8, 2014. Hide Caption 42 of 43 Photos: The search for MH370 Malaysia Airlines Group CEO Ahmad Juahari Yahya, front, speaks during a news conference at a hotel in Sepang on March 8, 2014. "We deeply regret that we have lost all contacts" with the jet, he said. Hide Caption 43 of 43

The search zone for Wednesday shifted eastward toward the Australian coast from what it had the day before, according to the Australian Maritime Safety Authority. While this means new territory will be covered, officials caution against expecting an imminent breakthrough.

"It will take time," retired Air Chief Marshal Angus Houston, the head of the Australia's new Joint Agency Coordination Centre, said Tuesday. "It's not something that's necessarily going to be resolved in the next two weeks."

The plane disappeared over the waters between Malaysia and Vietnam, after signing off with Malaysian controllers, but before checking in with their counterparts in Vietnam.

Authorities don't know what happened on board after that, but radar and satellite data show the plane turned off course and flew back across Malaysia before turning south over the Indian Ocean.

Based on sophisticated analysis of satellite data, investigators believe it went down in the southern Indian Ocean, but they can't pinpoint a location.

A Malaysian government source told CNN on Monday that the airliner's turn off course is being considered a "criminal act," either by one of the pilots or someone else.

In a background briefing given to CNN, Malaysian investigators said they believed the plane was "flown by someone with good flying knowledge of the aircraft."

A senior Malaysian government official last week told CNN law enforcement analyst Tom Fuentes that authorities have found nothing in days of investigating the two pilots that leads them to any motive, be it political, suicidal or extremist.

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"It's one of the great mysteries of our time," Australian Prime Minister Tony Abbott said in a radio interview Wednesday from Perth, where he'll host his Malaysian counterpart Najib Razak later in the day. "...We owe it to the world, we owe it to those families to do whatever we reasonably can do get to the bottom of this."

More help on the way

Chinese relatives of passengers got a chance Wednesday to learn how the search is unfolding and how it's been concluded that the flight ended in the Indian Ocean.

Malaysia Airlines and Malaysia's Department of Civil Aviation led a closed-door briefing with the Chinese kin in Kuala Lumpur, the Malaysian government said. Technical experts from Malaysia, China and Australia were also expected to participate, as was the Chinese ambassador to Malaysia.

Meanwhile, even more assets are contributing to the search.

Hishammuddin tweeted the HMS Tireless, a British nuclear submarine, will take part. It'll be joined by an Australian ship with a pinger locator designed to listen for locator beacons attached to the plane's flight data recorder plus a submersible capable of canvassing the ocean floor for wreckage. Both pieces of technology come from the U.S. Navy.

The equipment won't be of any use, however, until searchers are able to find wreckage from the plane to help narrow the search zone.

That's because neither the pinger locator nor the submersible can quickly scan the enormous area being searched.

Under the best of sea conditions, the pingers can be heard 2 nautical miles away. But high seas, background noise, wreckage or silt can all make pingers harder to detect.

It will take the ship, the Ocean Shield, two more days just to get to the search zone, leaving precious little time to locate the flight data recorders before the batteries on its locator beacon run out.

Time is running out: The batteries are designed to last 30 days. Wednesday is the 26th day that authorities have been looking for the plane.

There's no guarantee it will be found anytime soon. For all the expertise and technology, there's still more unknown about Flight 370 than is known about it -- including its altitude, precise speed and, especially, its final resting place.

As CNN aviation analyst Miles O'Brien said: "We're seeing what amounts to a big guess."