A gang of bumbling burglars dressed as Japanese Ninja warriors has botched most of its heists in the Concord area so far, managing to burn up $7,000 while trying to open safes with a blowtorch. But police say the group of three or four people is getting better with practice, and last weekend, in their fifth known job, they escaped with about $500 in unsinged cash. The gang members dress in black like the Ninja, a feudal Japanese society of mercenary assassins, and enter buildings through a roof or by forcing employees to let them in. "They started out like they've been watching too many movies," said Detective Rich Berendsen. He said in three burglaries, the gang's blowtorches burned up most of the cash. The gang's first known burglary was at a local restaurant on Jan. 25, but they gave up trying to break into a safe when their drill bit broke off in the lock, Berendsen said.