In fact, the contract killing example you gave is a classic illegal agreement / contract. (law.stackexchange.com)
Japanese auto parts manufacturer Mitsubishi Electric has been fined $ 13.4 million after pleading guilty to participating in illegal agreements with industry competitors to determine who would win certain calls for bids issued... [more] Full article (thelitigator.ca)
See the Wikipedia articles on illegal agreements and contract killings. (law.stackexchange.com)