Tome of Strahd Found at Winery; Players Suspicious

Howdy! Our campaign has been going smoothly so far and I'm having a lot of fun adding additional elements from the resources found on this subreddit. I'm thankful for this awesome community.

My players just wrapped up the last of the combat encounters at the winery and have found the Tome of Strahd in the glassblowing shop. They are currently freaking out at the potential connection the Martikovs have to Strahd and are very suspicious of them.

How would you go about explaining why the tome was in their barrel? How would you continue to build trust moving forward?

Our last session ended just before the party got the chance to debrief with the Martikov's, so the start of the next session will begin with that roleplaying opportunity.

Thanks for any insight you can provide!