Power Line interference with different Sampling frequency
That depends if the bandpass filter was applied before or after sampling. If it was before sampling (i.e. in analog domain) it worked as an anti-aliasing filter and you dont need to filter out the PL. If it was applied in digital domain, you'd need to suppress it, because then the aliasing would occur. Have a look at the FFT of your signal to see if there is a peak or not at 14Hz, which could come from the PL.

(I guess the filter was applied in analog domain, because it does not make much sense to do it after sampling, since the high cutoff is already the Nyquist frequency.)