What would you do? Deceased Bio Dads family now wants visitation

Hello… My child’s father was murdered 15 yrs ago due to drugs. I’ve moved 10 hours from them when pregnant and his family has had nothing to do with my child. They have never even sent my child a birthday card. Well my child’s grandmother (father’s mom) overdosed last yr along with 6 other family members. Now all of a sudden my ex sil wants to fly my child upto her for several weeks to spend time with her & her kids… I’m pretty hesitant to do so. Yes I’ve personally taken my child to see them 3 times over the last 15 yrs but when they’ve come to our area, they haven’t bothered to even see my child. Ive made all the effort all of these years for them to have a relationship to no avail and now they want a relationship? They have even began texting my child behind my back trying to make plans which I’m not too happy about…
AITAH if I say no? What would you do in this situation?

I personally would not want my child around the drug use. Take the child there yourself and that’s it. Trust needs to be built before you send your baby off.