TORONTO -- When police started receiving reports of phones being stolen at a Sum 41 concert in Amsterdam, they didn't have to go far to find the alleged culprit.

All they had to do, Dutch police said Monday, was block the exits and look for the man who had somehow stuffed 30 cellphones into his cycling shorts.

Police said they had been tipped off about possible pickpocket activity at the Canadian punk band's concert by authorities in Antwerp, Belgium, who had been informed of approximately 50 stolen phones during a Sum 41 gig a few days earlier. Because of that, they had extra personnel at the concert hall, watching specifically for phone thefts.

A 34-year-old man from Romania was arrested at the Jan. 21 concert and held in custody. Police have not publicly said what charges he is facing.

As for how he was able to fit so many phones into the pocket-less shorts, police said he was wearing other pants over the cycling shorts, and the hidden shorts were so tight that they were able to hold the phones in place.

Police said phone thefts are an increasing problem at concerts, especially ones involving punk and other genres that encourage moshing.