Rep. Murphey discovered the transactions by searching Oklahoma's Open Books website. It appears that the payments began with the start of the FY2011 budget in July of 2010. A quick search of the state spending site shows no previous transactions with any Planned Parenthood vendor.
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The money was paid by the State Department of Health. At this time, it is not sure what exactly those payments were used or intended for, but since this has come to light, you can be sure that it will soon be known.