leah porter was killed in 2014 and the keller is talking about the crime. jim avila is in los angeles. why did christopher talk and what did he have to say? : there's a couple storylines you want to follow tonight on 20/20. we are talking about this young man, a 23-year-old criminology student. how he used what he learned in his class to try to cover up his crime and how it almost worked, we talked to him in prison. he told us things he did not tell police, including his motive. the second story line is about lee porter's brother who launched a parallel investigation to the police, and got christopher wade one on one in a gazebo in colorado and got him to confess and got it all on tape. jummy: i understand you also spoke with christopher's professor from school. what are some of the things he said? jim: that is what is interesting about the first storyline. christopher wade was in a criminology class and allegedly was gathering information to carry out the perfect crime. the professor now tells us that in fact he thinks that is what happened, that he learne

. >>> the family of leah porter was on 20/20. they just want to find her body. she disappeared in 2014 and it was porter's brother who ended up getting the killer to confess. recording it on his cell phone. >> she -- i placed my hand at her throat, i didn't start squeezing until after she kept going. i thought the -- her muscles gradually move the knife away and let her go and let her regain consciousness. but that didn't happen. >> even with that confession, christopher wade was offered a plea deal that ended with a 48 year sentence. that could have been longer but leah's body still has not been found. >>> a handful of students and their bus driver are recovering after this crash. they were rushed to the hospital after getting accident. three other cars were involved. one of the other cars lost control, hitting the bus. the bus was taking 34 denver students home. none of the injuries are serious. -?>>> a teen has been arrested, accused of starting the largest wildfire in our state right now. the beaver creek fire is burning north of walden. investigators aren't