Disappearance of Busan Newlywed

In 2016, a prominent Busan couple, Choi Sung Hee and Kim Yoon Suk disappeared in thin air, just 6 months into their marriage. There were last seen in CCTV entering their apartment, but none of them were ever seen leaving their apartment. Their grocery was untouched and they left behind a dog. There was no sign of them on CCTV even though there were so many of them.