Malaysian police are still searching for a Pakistani national over the alleged theft of money from bank accounts belonging to four people aboard missing Malaysia Airlines Flight 370, according to Malaysian investigators.

"We are still trying to locate this Ali Farran, who last worked as a car mechanic," Assistant Commissioner Izany Abdul Ghany of the Kuala Lumpur Commercial Crime Investigation Department said Monday.

Authorities have arrested two people in relation to the alleged theft: an HSBC bank officer and her husband.

The bank officer is accused of using Internet banking to transfer money from four passengers' bank accounts into another passenger's account.

About $10,000 (35,000 Malaysian ringgit) was then allegedly transferred to a fifth account belonging to Farran, police said.

In total, about $35,000 (110,600 Malaysian ringgit) was reported missing from the accounts of two Chinese passengers, Ju Kun and Tian Jun Wei, and two Malaysians, Hue Pui Heng and flight steward Tan Size Hian.

Police have yet to charge the couple, who have been in police custody since their arrest on Thursday.

"We have extended the remand order for the two until Wednesday to facilitate in the investigations," Izany said.

HSBC's Malaysian branch said it notified police of potential fraud involving the accounts.

"HSBC is deeply sorry for this incident and apologizes to the families of our customers for the distress this will cause and assures them there will be no losses on these accounts," a spokeswoman said.

Flight 370 went missing en route from Kuala Lumpur to Beijing on March 8. Extensive land and sea searches have failed to find any sign of the Boeing 777-200ER, which was carrying 227 passengers and 12 crew.

It's believed the plane crashed into the southern Indian Ocean, west of Australia.

This month, Australian officials announced that Dutch company Fugro Survey would take over the next phase of the search, which was likely to start in September.

The company will use two ships equipped with towed deep-water vehicles, as well as side-scan sonar, multibeam echo sounders and video cameras, to search an area of 60,000 square kilometers (23,000 square miles) and depths of up to 7,000 meters (four miles).

(CNN)