A man seen with a knife on his person yesterday in the Washington Mall is being sought by police.A police spokesman said a group of males entered the mall at 4.15pm, with one walking with a cane and carrying what appeared to be a six-inch knife.The suspect was described as wearing a grey hoodie and tan pants.Officers attended and carried out an extensive search including the bus terminal, City Hall and other parts of the city for anyone fitting that description.They also viewed police and mall CCTV video, but without success.It marked the second incident involving weapons at the mall in two days, after gunmen yesterday targeted a gold shop in an early morning raid.