Tourism officials in Seattle have launched a social media campaign to find Sam – a Vancouver man who was caught with his family in Tuesday's May Day riot and had the windows of his SUV smashed.

In recent days, Sam has become a Seattle celebrity after he was captured by television cameras in the aftermath of the May Day protest.

Now his picture is all over the internet and the city of Seattle wants to treat him to a free vacation.

Sam had been shopping in downtown Seattle with his family when they got caught up in the centre of the riot.

While he and his family took shelter in a nearby building, the protesters smashed his car windows and others took pictures of the damage, heckled him, called him a hoser and told him to go back to Canada.

He was interviewed at the time by a Seattle television station but only gave his first name.

"This gives me a real nice impression of the [United] States, doesn't it? And then to have other people taking pictures and telling me to 'Go back to Canada you hoser,'" he told KIRO news.

Police quickly moved in to corral the Seattle protesters, leading to several arrests. But now Seattle Tourism officials want to offer an apology and a free trip back to the emerald city.

They have since launched campaign on twitter called #findsam in an effort to use the power of the internet to track him down.

Apart from his name, officials know he is Asian, appears to be in his forties, lives in Vancouver and drives a black, newer Hyundai SUV with a Jim Pattison license plate cover.