All the 36 states governors in Nigeria have called for thorough investigation into the immediate and remote causes of the helicopter crash that killed former Kaduna State Governor, Patrick Yakowa and five others on board.

The governors, under the body of the Nigerian Governor's Forum (NGF), made the call in Kaduna during a condolence visit to newly sworn-in Governor Mukhtar Yero.

Chairman of the forum, Governor Rotimi Amaechi of Rivers State said the forum insisted on transparency and openness in the process.

Amaechi said the visit was to condole with the family and the people of the state over the tragic death of the former governor, and expressed the forum's support to the new governor, urging him to strive hard towards accomplishing the set goals of his predecessor.

Following the helicopter crash which led to the death of Yakowa and the National Security Adviser, Gen. Andrew Azazi on Saturday, President Goodluck Jonathan directed that the crash be investigated.

Others involved in the ill fated Navy helicopter crash were their aides, Dauda Tsoho and Warrant Officer Mohammed Kamal and the pilots, Commander Muritala Mohammed Daba and Lt. Adeyemi O. Sowole.