TWO-HOUR '20/20' REPORTS ON THE MURDER OF MANDY STAVIK, THE COLD CASE SOLVED AFTER NEARLY 30 YEARS

Details How the Killer's Co-Worker Cracked the Case With Used Water Cup From the Office

'20/20' Airs Friday, May 29 (9:01 - 11:00 p.m. EDT), on ABC

In 1989, 18-year-old Amanda "Mandy" Stavik disappeared while jogging in her rural Washington hometown and later police discovered her body in a nearby river. News of her rape and murder shook her tight-knit community, but with no leads and police unable to find a DNA match to her killer, the case went cold for decades. Just last year, a jury found a former neighbor of Mandy's, Timothy Bass, guilty, finally bringing an end to the nearly 30-year-old case. A two-hour "20/20" unfolds the details of how police got their man, including the key role a colleague of Bass' played in cracking the case. "20/20" airs Friday, May 29 (9:01 - 11:00 p.m. EDT), on ABC. (Rebroadcast. ABC OAD: 9/20/19)

"20/20" is anchored by David Muir and Amy Robach. David Sloan is senior executive producer.