There is a Dragnet episode similar to this.
An older lady knew about a scam going around and called Friday and Gannon to catch him at her house. Gannon pretended to be her son.
I forget what the scam was.
I believe it was two guys posing as cops trying to catch some counterfeiters passing bad $100 bills.
So they would target old folks, telling them to withdraw
their savings in $100 bills, hand it over to them so they ‘’match’’ it against the phonies. They then would give the ‘’mark’’ a receipt for the money to be reclaimed which of course it never was.