Brazilian authorities have arrested three more men suspected of taking part one of the world's biggest cash heist, and a fourth allegedly has been kidnapped, officials said Thursday.

Pedro Jose da Cruz, Anselmo Oliveira Magalhaes and Leonel Moreira Martins were arrested in early November in Sao Paulo, federal police spokeswoman Erotildes Bezerra said. It was unclear why the arrests were not announced earlier.

Authorities are tracking at least six more suspects, including one of the alleged leaders of the gang that tunneled under a city street in August and stole more than $70 million from a branch of Brazil's Central Bank in Fortaleza, 1,500 miles northeast of Sao Paulo.

So far, authorities have recovered about $8 million of the stolen money. Five men were arrested in September with about $5.4 million of the money from the heist and told police they helped dig the tunnel.

Meanwhile, police in Fortaleza were searching for Jose Elizomarte Fernandes Vieira, a car dealer suspected of laundering money for the robbers. Vieira was kidnapped Tuesday, investigator Luis Carlos Dantas said.

It would be the third kidnapping related to the heist.

In late November, the wife of a bank security guard suspected of providing information to the robbers was kidnapped. She was released three days later after her abductors found her husband's share of the money.

In October, Luis Fernando Ribeiro, the alleged brains behind the robbery, also was kidnapped. He was found dead two days later after his family reportedly paid $890,000 in ransom. Two policemen have been arrested in connection with the slaying. Police suspect the officers were hired by acquaintances of Ribeiro.