Yuval Steinitz
Yuval Steinitz Yonatan Sindel/Flash 90

Energy Minister Yuval Steinitz's brother-in-law was detained for questioning Sunday, along with other associates close to Steinitz, in the growing probe over Israel''s purchase off German submarines that has ensnared some of his top associates.

The relative in question,Gary Hakim, is the owner of the entrepreneur, construction and infrastructure company called Shafir Engineering. Other members of Steinitz's inner circle that were detained are Aviad Shai, who served as Steinitz's adviser during the years Steinitz served as Finance Minister, and Rami Tayeb, his chief of staff.

Police are now trying to examine a possible connection between Minister Steinitz himself and the submarine affair. The Attorney General has authorized police investigators to summon Minister Steinitz in order to provide testimony, but the police believe that the testimony will result in an official investigation.

Case 3000 started out as a conflict-of-interest investigation into whether Netanyahu's personal lawyer David Shimron improperly represented German shipyard ThyssenKrup. It has since widened to include top officials in Israel's security apparatus, such as former Israeli Navy Commander Major General Eliezer Marom, and Shai Brosh, a former commander of Israel's elite Shayetet-13 naval commandos.