At this point it could be anything, the only best way to approach this in my opinion is to always stay alert and make precautions for the most likely situations.
International Level: Senior Politician / Political Participation: 187 18.7%
I definitely would call police to alert them to patrol the neighborhood more often, and I might invest in a home security and front (And back?) door camera, if possible.
I've actually never heard of this before and see it happened in Australia. Has anyone heard of this happening in the U.S. Or elsewhere?
International Level: Politics 101 / Political Participation: 1 0.1%
This is one method but there may be more subtle ways of letting gang members know that your house might be vulnerable.
International Level: New Activist / Political Participation: 13 1.3%
This is something kids will do. Real thieves wouldn't do this. They have WhatsApp with geolocation to pin any place down so there is no need to put a physical mark to alert you or your neighbors that they are coming your way.
International Level: Politics 101 / Political Participation: 2 0.2%