The paper is concerned with an identification of a rigidity parameter for thin inclusions located inside elastic bodies. It is assumed that inclusions cross an external boundary of the elastic body. In addition to this, a delamination of the inclusions is assumed thus providing a crack between inclusions and the elastic body. To exclude a mutual penetration between crack faces, inequality-type boundary conditions are imposed. We consider elastic inclusions as well as rigid and rigid-elastic inclusions. To find a solution of the problem formulated, we solve an optimal control problem. A cost functional characterizes a displacement of the external part of the inclusion, and a rigidity parameter serves as a control function. We prove a solution existence of the problems formulated.