San Diego County prosecutors are warning residents about a scam tactic that brings criminals directly to victims’ homes.

District Attorney Summer Stephan told NBC 7 San Diego that courier scams have become the top fraud tactic seen locally, with scammers sending people to collect cash in person after victims are contacted by phone or through computer pop-up messages.

The shift comes as banks and retailers have become better at stopping wire transfers, cryptocurrency payments and gift card schemes. NBC 7 reported that in one recent Carlsbad sting, police arrested a suspected scam courier who investigators said was trying to collect $20,000 from an elderly victim.

The warning is especially relevant for Santee seniors and families checking on older relatives. Authorities said some victims are told to withdraw large sums of money, convert cash into gold bars or hand over ATM cards to someone posing as a trusted official.

Residents should not hand money, gold, bank cards or personal information to anyone who comes to the door after an unsolicited call or pop-up warning. Suspicious activity can be reported to local law enforcement, and the San Diego County Sheriff’s Department maintains elder abuse resources for residents seeking help.