Mr Wen was unable to account for millions of yuan in assets
A former senior police officer is on trial in the Chinese city of Chongqing on charges of corruption, rape and protecting criminal gangs.
Wen Qiang is accused of taking more than 16m yuan ($2.3m; £1.5m) in bribes to turn a blind eye to crime, Chinese media reported.
He is the most senior official charged under a corruption probe in the city.
The trial comes a day after another police official, Yue Cun, was sentenced to death for corruption.
Mr Wen is appearing in court alongside his wife, Zhou Xiaoya, and three other senior Chongqing police officials, in a trial expected to last four or five days.
Prosecutors say Mr Wen, the former director of the Chongqing Municipal Judicial Bureau, accepted vast sums of money from businesses, officials and criminal gangs in exchange for protection from the law.
When questioned, he had been unable to account for some 10m yuan in assets in his personal possession, the Xinhua news agency reported.
He is also accused of raping a university student on several occasions.
If found guilty, Mr Wen could face the death penalty.
Mrs Zhou had been charged with abusing her position as the spouse of a government official to illegally obtain some 8.16m yuan, according to Xinhua.
Xie Caiping was known as the Godmother of Chongqing
The three other police officials also face charges of bribery and protecting gangs.
The corruption investigation in the southern city began last summer and more than 780 people have been prosecuted.
Mr Wen's sister-in-law, Xie Caiping, was jailed for 18 years in November last year, for crimes including running gambling dens and protecting drug users.
Described as the Godmother of Chongqing, she was reported to have earned more than 2m yuan ($292,000; £179,000) from crime.
The BBC's Chris Hogg in Shanghai says the crackdown in Chongqing is being seen as an attempt by its party secretary, Bo Xilai, to secure a spot in the governing politburo.
He is considered one of the Communist Party's most popular and charismatic figures, and is clearly keen to show he is strong enough to tackle what seems to be endemic corruption, our correspondent says.