bù liǎo liǎo zhī

不了了之

settle a matter by leaving it unfinished; not tie up loose ends; to end up with nothing definite

Example:

此案因证据不足, 最后不了了之。
Cǐ àn yīn zhèngjù bùzú, zuìhòu bùliǎoliǎozhī.
Prosecution of the case fizzled out for lack of conclusive evidence.