DUBAI, June 29 (Reuters) - Saudi Arabia's securities regulator said it would form a committee to oversee Mohammad Al Mojil Group (MMG) after the Saudi Arabian construction firm's board resigned when three people involved with the business were found guilty of fraud.

MMG's board quit last week when the CMA sentenced three people, including founder Mohammad Al-Mojil and his son Adel Al-Mojil, the company's chairman, to between three and five years in prison.

The three were found guilty of manipulation and fraud relating to the MMG's initial public share offer in 2008 - a decision which the company said was based on "fundamentally flawed" evidence. The CMA also ordered payment of 1.6 billion riyals ($427 million) in damages.

On Wednesday, the CMA said it would appoint an interim committee to supervise MMG until a general assembly of shareholders was formed within three months to elect a new board of directors.

The three-member committee will be chaired by Abdulrahman bin Abdulmohsen Al-nafea, a lawyer who has served as an advisor to the CMA. The regulator did not say when the committee would start operating.

(Reporting by Andrew Torchia; Editing by Alexander Smith) ((andrew.torchia@thomsonreuters.com; +9715 6681 7277; Reuters Messaging: andrew.torchia.thomsonreuters.com@reuters.net))