(Reuters) - A top SandRidge Energy Inc
Mount Kellett Capital, which holds about 4.5 percent in SandRidge, said in a letter on Thursday that it was reviewing allegations by another investor, TPG-Axon, that Ward and his son acquired mineral rights and sold them to SandRidge or other oil and gas companies at a profit.
It said the company's board should hire an independent law firm and a forensic law firm to look into the allegations, and that Ward should be suspended until completion of the probe.
WCT Resources - an Oklahoma company owned by trusts benefiting Ward's three adult children and run by his son, Trent - is a business partner with SandRidge, according to SEC filings.
The company has paid WCT nearly $5 million since 2008 to lease property controlled by WCT in northern Oklahoma and for royalties on wells operated by SandRidge on the land, according to an analysis of SEC filings.
Mount Kellett COO Jonathan Fiorella said in the letter that it would "seem reasonable to infer ... that WCT leveraged SandRidge's and Mr. Ward's knowledge of the Mississippian play, at the expense of SandRidge shareholders, to acquire properties at a time when the play was just emerging."
SandRidge is the largest operator and was one of the earliest companies to acquire acreage in the Mississippian - a rock formation that spans northern Oklahoma and southern Kansas. WCT has also acquired land in the region.
Hedge fund TPG-Axon Capital and Mount Kellett have been pressing to replace Ward and the board and to put the company up for sale.
SandRidge could not be immediately reached for comment. The company, which has been searching for a strategy to improve returns, has come under fire from investors because its shares have underperformed peers.
The company, which has shifted its focus from natural gas to oil in reaction to falling natural gas prices, made a steep cut late last year to its estimates on how much oil it believes it can recover from key wells in the Mississippian.
Ward bought into SandRidge's predecessor and took over the company in 2006 after leaving Chesapeake Energy
Chesapeake had to contend with its own governance and performance problems last year, and McClendon has been stripped of his title of chairman of that company as a result.
(Reporting by Michael Erman; Editing by Sriraj Kalluvila, Theodore d'Afflisio and Nick Zieminski)