Prosecutors at the Norfolk County Superior Court in Massachusetts share new details in the murder case against disgraced art salesman Brian Walshe, just two months after they finished one of the biggest trials of the year -- Karen Read. And Michael Proctor, the lead investigator in both cases comes under fire from the defense.  Five years after an Arizona man was accused of robbing a young woman named Mercedes Vega, he is charged with her murder. Updates in the Karen Read and Sean "Diddy" Combs cases, plus jailhouse phone calls from convicted killer Brooks Houck. And how crime scene technicians can make or break an investigation.

Find out more about the cases covered each week here: www.datelinetruecrimeweekly.com

Listen to the NBC Boston podcast ""The Searches for Ana Walshe"" here: https://www.nbcboston.com/news/local/brian-walshe-murder-case-podcast-searches-for-ana-walshe-new-episodes-out-now-where-to-stream/3785005/

To learn more about Dateline LIVE in Nashville on Sept. 28, and to get tickets, go here: https://www.nbcnews.com/dateline-event