Lidiane Leite has been on the run for 12 days, with no clues to her whereabouts, a Federal Police delegate from the northern state of Maranhao told CNN.
"She is the most wanted person in Maranhao now," Max Ribeiro said. "She can't hide for much longer."
Leite, 25, was the mayor of the town of Bom Jardim, which is about 275 kilometers (170 miles) southwest of Sao Luis, the capital of the tropical Maranhao state, which borders the Atlantic Ocean.
She is being investigated by authorities, accused of siphoning off funds earmarked for school lunches and refurbishments. She has been indicted, but apparently doesn't have an attorney at this time.
Leite enraged local residents by posting pictures of herself at nightclubs and parties in Sao Luis and is said to have sent messages to her Cabinet via WhatsApp.
"She started flaunting a luxurious lifestyle that her salary couldn't afford," Ribeiro said. "She was traveling, doing plastic surgeries and buying expensive cars."
"There were also complaints that she was leaving town every week and sending orders over phone apps like WhatsApp," he added.
Leite was removed from her post on Sunday after officially abandoning her office for 10 days. Her deputy was sworn in as interim mayor.
Many residents in Bom Jardim -- a town of 39,000 in one of Brazil's poorest states -- have taken to the streets to demand an end to corruption.
In total, Federal Police believe that more than $1 million was siphoned off in a corruption scheme also involving other members of the local government.
According to Ribeiro, Leite's boyfriend at the time, Beto Rocha, ran for mayor of Bom Jardim back in 2012. But two days before the vote, he was barred from participating in elections because of allegations of corruption, and Leite stepped in to replace him.
Rocha, now her ex-boyfriend, was arrested as part of the current investigation into Leite. He's been indicted and is in jail.