A Turkish criminal court yesterday acquitted retired Brigadier General Levent Ersöz of charges of having killed Turkey's eighth president, Turgut Özal.Ankara's fourth High Criminal Court said that there was a lack of positive proof for the charges.Ersöz's lawyer cited a secret witness who had said that Özal's wife Semra had poisoned the president, and pleaded that Semra Özal should be tried on the charges.Özal died of a suspicious heart attack on April 17, 1993 while still in office.