Any advice on aa cold case?

In 1987, a beautiful young lady was sexually assaulted, bludgeoned, then strangled to death, in about a 15 minute frenzied attack. It was the morning of her 26th birthday, and she was on the phone with her mom because they were leaving for a birthday trip to Hawaii for a week and planned on leaving for the airport soon. Her mom said her daughter suddenly screamed and the phone went dead. She called 911 and raced over to her cabin. The police arrived at the same time as the mom, about 15 minutes from the scream.



This happened in my town, and it has haunted me ever since. While I have worked with, and have respect for LE, they really dropped the ball on this. I spoke at length with the victims mother a few years ago, and she said she eventually stopped calling to check on progress on the case after years of them dismissing her requests and finally stopped taking her calls.



I have many questions and theories. I have located some former co-workers and friends of the victim willing to talk to me. They have confessed to being confused about why they were never interviewed by LE.



I have called and emailed the proper LE agency, but have never been replied back to.



Though I worked as a Private Investigator, I let my license expire a long time ago. Can anyone advise me? Can I legally interview these women? Then how do I get someones attention if I find out anything?



Thank you.