Cindy McCain, the widow of former US Senator John McCain, has apologised after police disputed her claim that she stopped a human trafficking case.

Mrs McCain told KTAR radio she thwarted a crime by alerting Phoenix airport police to a woman of a different ethnicity than the child she was with.

But Phoenix police told the station on Wednesday that they found no criminal wrongdoing after performing the check.

Critics on social media have accused her of racial profiling and harassment.

What exactly happened?

“I came in from a trip I’d been on and I spotted – it looked odd – it was a woman of a different ethnicity than the child, this little toddler she had, and something didn’t click with me,” said Mrs McCain, 64, who also co-chair’s the Arizona governor’s anti-trafficking taskforce.

“I went over to the police and told them what I saw, and they went over and questioned her, and, by God, she was trafficking that kid,” she told the radio station on Monday.

“It was a toddler. She was waiting for the guy who bought the child to get off an airplane,” she added.

Phoenix police told local media that on the date in question – 30 January – police performed a welfare check based on Mrs McCain’s tip, but found “no evidence of criminal conduct or child endangerment”.

Mrs McCain, who has an adopted daughter from Bangladesh, later took to Twitter, saying: “I reported an incident that I thought was trafficking… I apologise if anything else I have said on this matter distracts from ‘if you see something, say something'”.

What has the reaction been?

Critics have attacked Mrs McCain, claiming that she had police “harass” an innocent family due to her own racial profiling.

Many more found her claim puzzling, considering that she herself has a daughter that is a different ethnicity from her.

Many also took issue with her apology, which they note did not include a direct apology for falsely claiming to have prevented a genuine trafficking case.

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Others defended her for alerting police to her hunch.

Last year, Southwest Airlines issued an apology after asking a California woman to prove that she was the mother of her bi-racial son.

Human trafficking is the fastest growing criminal enterprise in the world, according to the United Nations.

Trafficking in the US often spikes around the time of the Super Bowl in early February, as experts recently told BBC News’ Cut Through the Noise Facebook show (best viewed on mobile).