Ca, 65, was arrested by Quang Ninh Police for allegedly receiving the money from Truong Xuan Duoc, 52.
Ca said he had kept the sum intact and had submitted it in full to investigators. Ca’s arrest is part of an investigation into tax evasion and illegally trading State coffer invoices.
Investigators have found that a group of people formed "ghost" companies to illegally purchase the invoices and evade taxes.
Duoc and his wife, Nguyen Thi Ngoc Anh, 44, and Truong Van Nam, 33, have also been arrested. They all live in Hai Phong City.
Three other individuals have been placed on house arrest for the duration of the investigation.
Police said that Duoc has had a long-time relationship with Ca. Duoc helped some individuals at Dong Thieu Thermal Company purchase the invoices to evade taxes, investigators said.
Ca used to work for the Thuy Nguyen District Police in Hai Phong City, and he was later Head of Hai Phong Police Advisory Agency. In July 2010 he became director of the Hai Phong Police Department and held the chair for nine years before retiring.
In 2012, Ca was the highest-ranking Hai Phong police official on the scene during the arrest of Doan Van Vuon. The arrest and preceding shootout caught public attention. Six officers were injured by gunshots fired by Vuon’s family members.
Police had raided Vuon’s property to seize his land. The land seizure, however, was determined illegal by the Prime Minister’s Office and several officers were punished for damaging Vuon’s property.