he has known irvan since anthony was 17 years old. this year, he started training him for another shot at gold. >> he arrived in my place, eight weeks before the olympic trials. didn't seem as confident as i felt he need to be for the games. then he became anthony again. anthony has the most brilliant sprint freestyle stroke on the planet. the stroke carried him to one of the fastest times he ever posted at the olympic trials earlier this summer. and earned him a tick tight rio. >> wasn't like i demanded this of myself. >> reporter: you didn't stay i am getting back in the pool and going to make the next olympics. >> no way. he has no expectations for the future, but more importantly no regrets about the past. >> i really try to aindividual regret. i don't think anybody should be stuck in the past. that's a dead life if you are stuck in the past. life moves forward. >> because irvan helped the u.s. swim team win the 400 relay race here, ties for the record for longest gap of a u.s. swimmer between medals. 16 years set way back in 1924

. >> gary hall, anthony irvan. share the gold. >> instead, it led to the most tumultuous time of his life. >> part of what led to a lot of the angst initially was doing well and performing well, the social kind of like joy that comes from others and knowing that one has done well, and you kind of get hooked on that. you kind of need that to sus sustain yourself. ervan's parents are jewish, native american and african-american. >> the first swimmer of african-american descent to make the u.s. team. >> the only problem he never identified as a black man. >> did it really piss you off when people called you the first african-american swimmer? >> i wouldn't say it pissed me off, but it created an an immense amount of confusion. >> at the height of it all, he 2003. >> post olympic champion status was about rediscovering, rebuilding myself, the way i wanted to be not the way others were, at least the way perceived wanted me to be. >> reporter: over the next decade, ervan sold his gold medal, donated money to charity and

life moves forward. >> because irvan helped the u.s. swim team win the 400 relay longest gap of a u.s. swimmer between medals. 16 years set way back in 1924. >> the "cbs overnight news" will toilet germs don't just stay in the toilet. disinfect with lysol bathroom trigger... ... and lysol power foamer. they kill 99.9% of germs. to clean and disinfect your bathroom... >>> mass shootings have become an all too familiar sight on television. this past week marked 50 years since americans first witnessed that kd anna werner take is a look back in a story for "sunday morning." >> it is a summer day in austin, as students at the university of texas stroll the campus. a day much like the one 50 years ago, long before anyone knew the term mass shooting. >> this is where -- >> yeah. >> it's the day and the spot claire wilson james will never forget. see the tower. >> oh, yeah. >> right over you. >> that day was august 1, 1966. walter cronkite anchored a special cbs news report. >> a deranged engineering student at university of texas climbed to a