Knocking on the door demanding money

[mackerelfish]

Hi, about 3.45 this afternoon we had a knock at the door - 3 young girls about 15 years old demanding money. We weren't in but my poor mother in law who was on her own answered and said they kept on knocking until she had to threaten to call the police. My mil's quite an assertive lady and not easily scared, but said these girls were quite aggressive, being right up at the door and kept knocking despite bring told she didn't have anything. We're off the bellenden road and have never experienced any threatening behaviour in the area before, just wondering if anyone else had a run in with this group today? Many thanks