The decision was made by the General prosecutor's office prosecutor Māris Leja, who is also overseeing another case of the state versus Lembergs, the long-standing mayor of the port city of Ventspils.
The prosecutor scrapped the decision to hand the case materials for starting criminal proceedings, and returned them to KNAB for further investigation.
The prosecutor's office has closed the criminal proceedings as the activities of Šlesers and Lembergs weren't found to be punishable by law.
The so-called 'oligarch case' involves a number of well-known people - Aivars Lembergs, Ainārs Šlesers, and Andris Šķēle among them.
Four years ago, criminal proceedings were started about suspicion of corruption and other financial crimes. A total of 26 companies and 11 persons were involved.
The case lead to the dismissal of the 10th Saeima by former president Valdis Zatlers, as the Latvian parliament voted against allowing to search the place of residence of former MP Šlesers.
Prior to this, KNAB had confirmed that Šlesers has been named a suspect in the so-called 'oligarch case'.
While on August 17th, it was revealed that Lembergs is a suspect in the case as well, upon which the mayor of Ventspils appeared on television, saying that he denies everything He was accused of 'dealing in power' for arranging vice-mayor of Rīga Andris Ameriks to be appointed to the Rīga Free Port board.
Beforehand, the proceedings against Andris Ameriks, chairman of Rīga Free Port, were also closed as investigations revealed that he had not tried to accept a bribe.