2010 Chrysler Sebring trunk pops open at random

For the past couple of months, the trunk of my car randomly pops open. A few times my neighbor has called to let me know it’s open again and he has closed it himself on a few occasions. I asked my mechanic about it and he said he was at a loss.
I now go out and check the trunk several times through out the day. Any ideas on what is going on or how to fix this?
Thanks

does your key fob have a trunk release? Could someone be sitting on it?