and you told me that that recording was greg konrath's voice, is that correct? es. >> reporter: whether out of conscience, revenge, or fear, konrath's confidant is now ready to spill the beans. when we return, the trauma surgeon is back from the beach. and about to go into the box with detective rogers. >> what's the red light for? >> it's recording. >> oh, okay. >> reporter: and has even more bombs to drop. >> i used a knife. i tried to stab myself and hit my heart. >> reporter: and later, dr. konrath on tape again. this time, ours. when "20/20" continues. >> you comfortable? >> yes. (queen's "you're my best friend" plays) ♪ ooh... you make me live, ♪ whatever this world... at petsmart, we know that pet adoption changes lives. that's why petsmart charities helps save more than a thousand homeless pets every day! join us! no matter where you adopt, come to petsmart for a free adoption kit with over $400 in coupons. ♪ i really love you it's our gift to you for providing the greatest gift of all. ♪ you're my best friend! the human foot has always been good at... it