Deletes will remove the reference in memory but actual record will still exist on disk until it is overwritten. a cold start ( restart on the community edition) will force index to be rebuilt from disk.
Please see the following:
If you have a cluster of nodes with at least replication factor>=2 you may be able to use this option to ensure that the restarted node is re-indexed from its peer after data is replicated.
http://www.aerospike.com/docs/reference/configuration/#cold-start-empty