For the second time in a week, a local liquor store told police that a robber threatened a clerk and fled with cash.Lawrence Police say an unidentified man walked into Diane’s Liquor, 1806 Mass., and demanded money from a 49-year-old female employee. The clerk said the man indicated he had a weapon, but never displayed it.The man fled southbound on foot with an undisclosed amount of cash.It is the third such robbery in a week. Another liquor store along 23rd street was robbed last Tuesday, and late last week a clerk at Kwik Shop, just a half-block away, reported that a man with a similar description robbed the store.