Can a detective issue a warrant on us after several months?

This past november after buying a box of sudafed we were pulled over and swarmed by sherriffs which led to a vehicle search where they found the box of sudafed and about a dime sak of weed. They let us go after agreeing to set up a bust buy on anything or anyone. We set up a buy for a cpl pounds of weed. Which took about a week to set up. The day of the deal the detective said to put it off for a few days. A week goes by and we dont hear anything then we played phone tag for a week or so with the detective. Now six or seven months later the detective called and said he was signing a warrant on me and my husband for possession and chemical something since my husband didnt follow thru with the plan... As the detective put It. Can he stil sign a warrant on us after so long?