Upper panels: Fourier spectra of the transit timing variation of our best candidates. The horizontal dashed lines show the 5 s.t.d detection level, while the curves denote the frequency dependent, bootstrap false alarm probability (fap) of peak detections. Spurious peaks are denoted by vertical dashed lines in the case of KOI-186. Middle panels: folded TTV curves by the best periods. In case of KOI-977 the highest, 101.5 day peak was used. Lower panels: transit shapes of the best candidates.