A man calling himself the non-league robber tricked his way into a football team's changing room and stole their mobile phones.
Sidley Football Club were losing 3-0 at Crowborough Athletic and trudged disconsolately in at half time - only to find many of their belongings missing.
The angry footballers rang one of the phones and a voice at the other end said: "Unlucky mate - you've just been done over by the non-league football robber."
Amateur clubs across the county were warned to take care with their belongings as it emerged there had been a string of similar thefts.
The Sidley players - distracted by frantically having to cancel cards and phones - let in another four goals in the second half to lose 7-0 in the Tuesday night match.
Andy Laskey, the manager of Sidley Football Club, who play near Bexhill, said: "For someone to have the front to say that, I think there's a very real risk of him attacking any club."
The thief told groundsmen he was an assistant manager at Sidley and was allowed into the team's locked changing room at Alderbrook Recreation Ground in Crowborough during the Sussex County League match.
This is the second time the team has been targeted this season as a changing room was broken into in November while the club was playing at Wick, near Littlehampton.
About four years ago, club chairman Dickie Day's Toyota Avensis was stolen during a match.
Wick chairman Barry Wadsworth said the club's changing rooms were broken into three times in November and he had heard of similar thefts at Littlehampton and East Preston.
Sergeant Ruth Hammerton, of Uckfield police, said officers were considering descriptions and details of break-ins at other clubs to determine whether they were carried out by the same person.
Officers have invited the stewards from Alderbrook to help piece together an e-fit of the man.
Ms Hammerton said: "The fact this man has been boasting about what he's done means its likely he will attempt it again.
"I would hope football clubs are always vigilant, but especially so now, as this man is clearly targeting them."
Mr Laskey warned other teams to lock up valuables and be on the lookout after mobile phones, credit cards and cash were stolen from his players.
Anyone with any information can contact Sussex Police on 0845 6070999 or call the free and confidential Crimestoppers line on 0800 555 111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article