Ms Birbeck was last seen on CCTV in the village of Huncoat, near Accrington
, on August 12.
In less than two weeks the Black Cats will meet Portsmouth in the Checkatrade Trophy final at Wembley Stadium - but just three days later they are scheduled to be brought crashing back down to reality with the trip to Accrington
Stanley's Wham Stadium.
That game his since been rearranged on three occasions already, with Accrington
's FA Cup progression and Sunderland's Checkatrade Trophy success so far causing havoc with the fixture.
2 Who scored the only goal of the match for Accrington
at home to the Sky Blues in October 2017?
game has been moved to Tuesday, April 2 (7.45pm).
With a crowd within touching distance, cramped changing rooms complete with cold floor and chipped tiles and a sloping pitch far removed from the surface Derby are used to, Accrington
had plenty in their favour.
assistant Jimmy Bell said: "I'm incensed by the last couple of minutes."
Lee Birtwistle, 48, of Harcourt Road, Accrington
, pleaded guilty to failing to comply with the requirements of a community order.
He went on to be top goal scorer through his time in Leicester's youth and reserve sides, where he was given a year's contract and sent out on loan ironically to Accrington
Stanley in 2009 where he scored 9 goals in 44 games.
's best chance of the half came when Scott Brown played Kayden Jackson through on goal but Mickey Demetriou was alert to the danger and managed to clear.
upset the odds to knock out Championship high-fliers Preston North End in round one.