Dale Cregan operation "decimates" gangs in Manchester A huge gang-busting operation, launched by police after two officers were shot dead by Dale Cregan, has "decimated" organised crime in the area, officers said. More than 400 houses have been raided, 347 suspects arrested, nearly £1m of illegal drugs found and £2m in property seized by Greater Manchester Police. Operation Challenger targeted five crime gangs operating in Clayton, Droylesden and Tameside, the area of east Manchester where Cregan dealt drugs. It came after Cregan shot dead rival crime boss David Short and his son Mark, before going on the run and shooting dead PCs Nicola Hughes and Fiona Bone in Hattersley, Tameside, last September. Cregan was given four life terms last month.