Topological insulators are currently a subject of intense research and potential for spin-electronic devices. The breaking of gauge symmetry or time reversal symmetry(TRS) is a prerequisite for realizing new magnetoelectric effects. The broken TRS can be achieved by introducing magnetic ions to topological insulators. We have prepared the Fe-doped topological insulators FexBi2Te3, which are more metallic than the previous reported ones. This leads to the fundamental findings; the reentrant topologically insulating phase and topological phase transitions. Our study is aimed to characterize a nature of topological phase transitions in the case of randomly distributed magnetic clusters as well as to understand a reentrant topological insulating phase with valence-bond glassy behavior using muSR.