AI voice scams: hang up and call back on a number you know

Short answer

If a call or voice message says someone you know is in trouble, or asks you for money, hang up and call that person back on a number you already have. The FTC and the FBI both advise this. Do not pay while the caller is on the line, and never read out a code that arrives by text. A family phrase is an optional extra that the FBI advises, and we put it second, after the call-back.

Who this is for. Anyone with an older relative, or who is one. It needs 15 minutes with your family and no tools.

You cannot rely on your ear

In a 2023 study of 529 listeners, people detected deepfake speech (a computer-made copy of a voice) 73% of the time in both English and Mandarin, and training helped only slightly. The first author, Kimberly Mai of UCL, said in the university's release: "Our findings confirm that humans are unable to reliably detect deepfake speech, whether or not they have received training." (UCL news release, lab study, quote is a comment and not from the paper). A UK bank says voices can be cloned "from as little as three seconds of audio" (Starling Bank, September 2024, bank campaign).

So the plan has to work even if the voice is perfect.

Hang up and call back on a number you know

The FTC advises calling the person back on a number you know is theirs, to check the story (FTC, March 2023, regulator guidance). The FBI advises verifying a caller by hanging up and calling a number you find yourself (FBI PSA I-120324, 3 December 2024, government advice).

The FBI also says: "Do not send money, gift cards, cryptocurrency, or other assets to people you do not know or have met only online or over the phone." In May 2025 it added: "Never provide a two-factor code to anyone over email, SMS/MMS text message or encrypted messaging application" (FBI PSA, 15 May 2025).

Our additions:

• Call back from your contacts list. Redial and a number the caller read out do not count.
• If the caller says there is no time to call back, treat that as the reason to call back.
• If you cannot reach the person, call someone else who would know, such as another relative or their workplace. The FTC also suggests trying another family member or their friends.
• Tell a second person before you do anything else.

Practise the rule on six illustrative messages before a real one arrives.

Add a family phrase as a second check

The FBI advises creating "a secret word or phrase with your family members to verify their identities" (PSA, 15 May 2025; the December 2024 notice says "to verify their identity"). Starling Bank also suggests a family Safe Phrase that no one else knows and that is never shared digitally. No study we have read tests whether a phrase helps.

We put it second because the call-back works even if a relative forgets the phrase, and a phrase asked for on a call can be pulled out of someone who is frightened.

If you use one:

• Pick something nobody could guess from social media. The FBI also advises making social media accounts private.
• Never send it by text or email.
• Say it only when asked, and only by the person who is calling you.
• Change it after any use.
• If someone cannot recall it, fall back on the call-back.

Set it up in 15 minutes

1. Sit down with the relative and read the card below together.
2. Make sure the numbers on the card are saved in their phone under names they recognise.
3. Choose a phrase together, if you want one.
4. Agree who they tell. Name a second person.
5. In a week or so, call them yourself and say it is a drill. See whether they hang up. Tell them afterwards that it was you.

If a call or message says someone I know is in trouble, or asks for money:
1. Say: "I'll call you right back." Hang up.
2. Call <FAMILY_MEMBER> on the number saved in my phone.
3. If I cannot reach them, call <BACKUP_PERSON> on <BACKUP_NUMBER>.
4. Do not pay anyone while they are on the phone. No gift cards, crypto or
   transfers.
5. Never read out a code that arrives by text.
6. Tell <SECOND_PERSON> before I do anything else.
Our family phrase (if we have one) is kept <PHRASE_LOCATION>.

Replace the following:

• <FAMILY_MEMBER>: the person the caller claims to be, or "them".
• <BACKUP_PERSON> and <BACKUP_NUMBER>: someone who would know where they are, and their number.
• <SECOND_PERSON>: the person to tell, such as my daughter Elena.
• <PHRASE_LOCATION>: where the phrase is written down, or in our heads only.

Write the card on paper and keep it by the phone.

If the reader needs larger print, simpler words or another language, an AI assistant such as ChatGPT can reshape the card. Do not paste real phone numbers or the phrase into a chat (What not to paste).

Below is a card of steps for a relative to follow if a scam call comes in.
Rewrite it for <READER_NEEDS>.
Keep every step and the order. Do not add steps, and do not remove any.
Leave the words in square brackets as they are.
---
<CARD_TEXT>

Replace the following:

• <READER_NEEDS>: such as a reader who prefers short sentences and large type.
• <CARD_TEXT>: the card, with names in square brackets such as [daughter] and no real numbers.

Read the new card against the old one. Every step should still be there, in the same order.

Limits

Sources

1. FTC. Consumer alert on AI and family-emergency schemes, 2023. Regulator guidance. Link
2. FBI. Public service announcement I-120324, 2024. Government advice. Link
3. FBI. Public service announcement on AI voice messages, 2025. Government advice. Link
4. Starling Bank. Safe Phrases campaign, 2024. Bank campaign and commissioned survey. Link
5. UCL. News release on a deepfake speech listening study, 2023. Lab study. Link

Changes

1. v1.010 Oct 2026first version