attorney. someone matt knew very well. he so is good. and i would be lying if i said my heart was not in my throat. reporter: sam s defense attorney lew rosenblum was the former assistant d.a. who supervised the homicide unit. in fact, he was the original prosecutor who back in 1994 didn t think there was enough evidence to charge sam. not only that, lew was the man who brought matt into the homicide unit. lew took me under his wing and trained me how to do homicides. what s it like to go up against your mentor? well, it s terrifying to go up against your mentor. reporter: neither one of them had ever lost a murder case. but someone s winning streak was about to end. february 10th, 2015. 20 years after cathy torrez s murder, sam lopez went on trial. at the end of this case you are going to hold that man accountable for exactly what he did.
and just months before that trial began, matt murphy learned that sam had a new defense attorney. someone matt knew very well. he so is good. and i would be lying if i said my heart was not in my throat. reporter: sam s defense attorney lew rosenblum was the former assistant d.a. who supervised the homicide unit. in fact, he was the original prosecutor who back in 1994 didn t think there was enough evidence to charge sam. not only that, lew was the man who brought matt into the homicide unit. lew took me under his wing and trained me how to do homicides. what s it like to go up against your mentor? well, it s terrifying to go up against your mentor. reporter: neither one of them had ever lost a murder case. but someone s winning streak was about to end. february 10th, 2015. 20 years after cathy torrez s murder, sam lopez went on trial.
eight to bring him to trial. and just months before that trial began, matt murphy learned that sam had a new defense attorney. someone matt knew very well. he is so good, and would be lyin if i said my heart was not in my throat. reporter: sam s defense attorney lew rosenblum was the former assistant da who supervised the homicide unit. in fact, he was the original prosecutor, who back in 1994 didn t think there was enough evidence to charge sam. not only that, lew was the man who brought matt into the homicide unit. lew took me under his wing and trained me how to do homicides. what s it like to go up against your mentor? well, it s terrifying to go up against your mentor. reporter: neither one of them had ever lost a murder case. but someone s winning streak was about to end. february 10th, 2015. 20 years after cathy torrez murder, sam lopez went on trial.
and just months before that trial began, matt murphy learned that sam had a new defense attorney. someone matt knew very well. he so is good. and i would be lying if i said my heart was not in my throat. reporter: sam s defense attorney lew rosenblum was the former assistant d.a. who supervised the homicide unit. in fact, he was the original prosecutor who back in 1994 didn t think there was enough evidence to charge sam. not only that, lew was the man who brought matt into the homicide unit. lew took me under his wing and trained me how to do homicides. what s it like to go up against your mentor? well, it s terrifying to go up against your mentor. reporter: neither one of them had ever lost a murder case. but someone s winning streak was about to end. february 10th, 2015. 20 years after cathy torrez s murder, sam lopez went on trial.
that sam had a new defense attorney. someone matt knew very well. he so is good. and i would be lying if i said my heart was not in my throat. reporter: sam s defense attorney lew rosenblum was the former assistant d.a. who supervised the homicide unit. in fact, he was the original prosecutor who back in 1994 didn t think there was enough evidence to charge sam. not only that, lew was the man who brought matt into the homicide unit. lew took me under his wing and trained me how to do homicides. what s it like to go up against your mentor? well, it s terrifying to go up against your mentor. reporter: neither one of them had ever lost a murder case. but someone s winning streak was about to end. february 10th, 2015. 20 years after cathy torrez s murder, sam lopez went on trial. at the end of this case you are going to hold that man