Masked thieves broke into Burton Albion's Pirelli Stadium and stole valuables belonging to players and equipment before defacing replica shirts.
The three intruders, wearing hoodies, masks, and balaclavas, broke into the tunnel area at the League One club's stadium between 9.30 pm and 9.50 pm on Sunday.
CCTV footage showed the trio rummaging through kit crates before they decided to write their initials on a Burton home shirt left out for players to sign.
They were later picked up by cameras strolling across the pitch before climbing over a metal fence and leaving the stadium.
Burton said 'valuable items of first-team players' belongings and equipment were stolen from the tunnel area of the stadium following the squad's return from Stevenage. Signed merchandise was also defaced.'
They have appealed to the general public for help identifying the responsible individuals.
Pirelli Stadium bar manager Ben Robinson told ITV News: 'The things they've taken - it's not as if they can make any money from it. They've not stolen anything they can sell on.
'For me, it's a bit more personal, and pointless. They're not very nice people. They've got no respect for the club and people in general.'
The Brewers had boosted their League One survival chances with a 2-1 win at Stevenage on Saturday.
However, Tuesday night's 2-1 home loss to Cheltenham Town left them just one place and two points above the relegation zone.
Cheltenham, the team immediately below them, also still has a game in hand.
Burton plays at home to Reading this Saturday as they look to secure their third-tier safety.
Burton has asked anybody with information to contact hr@burtonalbionfc.co.uk in confidence.
