TAMPA — A woman explained in court records this week why she robbed three Brandon banks within 30 minutes in May, netting more than $6,000.She wanted to throw her daughter a graduation party.That, and the rent was late.Cindy Sanchez Carabeo, 50, of Valrico pleaded guilty in federal court Thursday to one count of interfering with interstate commerce by robbery, punishable by up to 20 years in prison.Her motives were briefly described in a signed plea agreement, filed Wednesday.In all three robberies, tellers were threatened with notes."Should you not follow these instructions you will meet your maker," one note said. "Should you not do as I say I will not hesitate to SHOOT."Another note threatened a teller with death but included the words, "Happy Mother's Day."Carabeo, who had no prior criminal record in Florida, was arrested the afternoon of the robberies.Deputies tracked her, still on the move, to an apartment complex, noting that her car was emitting red smoke from a ruptured dye pack, the court paper states.The arrest first drew attention because the robberies were so close together: at 3:19 p.m., 3:35 p.m. and 3:40 p.m. May 11, the Monday after Mother's Day.Times researcher John Martin contributed to this report. Contact Patty Ryan at [email protected] or (813) 226-3382.