Mexico invites US experts to investigate helicopter crash Mexico has invited experts from the U.S. National Transportation Safety Board to investigate a helicopter crash that killed the governor of the western state of Puebla and her husband

MEXICO CITY -- Mexico has invited experts from the U.S. National Transportation Safety Board to investigate a helicopter crash that killed the governor of the western state of Puebla and her husband.

Mexico's assistant transportation secretary says the invitation was made "to leave no doubts" about the Monday crash that killed opposition Gov. Martha Erika Alonso and her husband, ex-Gov. Rafael Moreno Valle.

Carlos Moran said Tuesday that the manufacturers of the helicopter and its engines will participate in the investigation, and it was too early to determine whether mechanical problems played a role.

Two pilots and a third passenger also died in the crash. The pilots were described as experienced, though one had spent much of his career flying fixed-wing aircraft.