Randy didn't know Cassie took on an undercover gig, and if he found out, he would most definitely lose his shit in a volcanic manner. It wasn't like she wouldn't tell him, she totally would, just not yet.
Tricia believed her husband disappeared because of his knowledge about a potential sex slave, and now there was missing money that Jenna believed to be Ryan's doing. Cassie could easily investigate Jason's disappearance while simultaneously checking out Ryan Seida on Jenna's behalf. It's a win-win situation.
She'd let Randy in on everything first thing Monday morning. This way she had a head start on the case.
The Seidas were obviously into some twisted shit. How twisted was the million-dollar question? Chills rippled down Cassie's spine. She probably won't be prepared for what's discovered.
Working every angle to get at the truth was the only way. She needed to get into Ryan and Kathy's home to nose around a bit. To do that, she needed to cozy up to them.