This app was mentioned in 7 comments, with an average of 1.43 upvotes
Indee, I also tested Silence & Signal. However, the search is not working correctly there, because it only searches for the contact but you cannot search for the content of the SMS.
Only App I currently found is the old SMS Messaging (AOSP) (https://play.google.com/store/apps/details?id=fr.slvn.mms). Maybe this code can be reused, if the feature was not actively removed.
Here is a link to the old messaging/sms app, because fuck hangouts, I uninstalled mine
Have you tried AOSP sms app https://play.google.com/store/apps/details?id=fr.slvn.mms
I think the ASOP Messaging App deletes when it reaches a defined number in a threat, check that out? https://play.google.com/store/apps/details?id=fr.slvn.mms&hl=en
Is this what you're looking for?
I had the same issue. I had to install AOSP ( https://play.google.com/store/apps/details?id=fr.slvn.mms&hl=en ), an older version of messenger and I was able to delete the messages.