A senior Chinese police official is being probed for alleged criminal links in the southwestern city of Chongqing, media reports said on Saturday.
Chen Honggang, the head of the highway police, is being investigated in a cleanup operation that began in June, in a preliminary step to legal proceedings, the Beijing News and China Daily reported.
The Beijing News said Chen had tried to commit suicide.
Several senior officials in the city of five million people have been netted in the cleanup drive over links to criminal gangs or for trying to protect the local mafia in return for money.
"The fight against the mafia has entered into its most difficult phase and we have to fight organised crime at the political and economic levels to achieve success," said Liu Guanglei, a municipal official.
According to media reports, the criminal gangs in the city are involved in -- among other things -- giving out illegal loans to the tune of 300 billion yuan (more than three billion euros), or a third of the city's annual revenue.
One of the architects of the clean-up drive is the city's new police chief, Wang Lijun.
According to the city municipality's website, 1,544 presumed gang members were arrested between June and mid-August.