This mum's method of interrogating her teenager on her whereabouts is simply brilliant.

We can all agree: Two 18-year-olds having a “movie night” before one leaves for college sounds absolutely implausible and one mum in the US wasn’t about to fall for it.

Heather Steinkopf, mother to 18-year-old Kaelyn Demmon from Ohio, is one savvy investigator.

Kaelyn and her best friend Stevie, 18, were having – actually having – a movie night before Stevie left town for college the next day, Buzzfeed reports.

But – as any mother and former teenager will know – having a “movie night” is so often code for something else entirely. Having a house party. Drinking too much. Playing Spin the Bottle and secretly hating it. Lighting bonfires. Doing something incredible stupid.

This mum challenged the school principal to take her 13 year old shopping. Post continues below.

Heather wasn’t falling for it. Not this time.

“Where are you? Before you lie where is your car?” she text messaged her daughter.

What followed was a series of tactical messages – cleverly delivered – to ensure Kaelyn and Stevie were where they said they were going to be, and unable to rely on a false alibi.

I think it’s safe to say my mom doesn’t trust me pic.twitter.com/67fUqUBUpI

— Kaelyn Demmon (@kaelyned) July 29, 2017

Heather requested a specific selfie. Then another. Then another. She wasn’t going to be fooled by what could possibly be previous photographs or editing tools.

Kaelyn posted images of the exchange to Twitter, with the caption “I think it’s safe to say: my mum doesn’t trust me”.

Understandably, her post has gone viral.

We've all been there, after all. And it's a handy trick for mothers to teenagers everywhere.

Over and out, Agent Heather. Job well done.