Only the most audacious, arrogant or amateurish thief would dare practise his craft in the presence of a web-slinging crime-fighter, a fleet-footed member of the Justice League and several light sabre-packing guardians of galactic peace and justice.

But the lure of a AU$160 (£97) X-Men omnibus proved too much for one comic book fan, who decided to slip the illustrated treasure into his backpack in an Adelaide bookshop on Saturday morning.

Sadly for the would-be shoplifter, he had not reckoned with the arachnid acuity of Michael Baulderstone or, more precisely, his CCTV cameras.

The 45-year-old owner of the Adelaide Comic Centre, who was dressed as Spider-Man, clocked a customer "behaving suspiciously" at the back of the shop. So he sprang – or rather loped – into action.

Security tapes of the incident show Baulderstone, resplendent in his blue and red crime-fighting costume, marching after the apparent thief before stopping him and confiscating his rucksack.

"We had about 40 people dressed up as their favourite superheroes to celebrate International Free Comic Day, so he didn't have much of a choice but to hand the X-Men omnibus back after a little bit of a scuffle," the shop owner told the Advertiser.

"I've had a look at the security footage and it shows Spider-Man running down the corridor of the shop, grabbing this guy, hauling him off."

Not altogether surprisingly, many customers initially believed the spider-citizen's arrest they had witnessed was a mere stunt.

"Everyone in the store thought it was a play, that it was street theatre of some sort," said Baulderstone. "It wasn't until I said: 'Call the police' that people started to realise."

As well as stumbling into a den of superhuman lawmen, the aspiring thief also managed to choose the one day of the year on which comic stores hand out free comics. The Adelaide Comic Centre and Pulp Fiction Comics were both giving them away to their loyal, costumed customers to mark International Free Comic Day.

"One of the funniest things about the incident was that I called for people to stand near the door and it just so happened we had people dressed as Jedi knights there blocking the exit, the Flash was there at some point too," said Baulderstone.

"It was a bit serious at the time, but now we're looking back laughing at what greeted police when they arrived."

David Humphrey, a member of the Rebel Legion group of Star Wars aficionados, said: "It was quite funny to think that our Spider-Man actually did catch himself a bad guy."