Some consumers have received their copies of Grand Theft Auto 5 in the post before the game's September 17th release date.
Additionally, other retailers have told MCV they had signed “incredibly strict” agreements with developer Rockstar, which demanded copies should not go on sale until midnight tonight.
Apparently some consumers received dispatched notices from Amazon on Friday, September 13th, and others received the game on Saturday, September 14th - three days ahead of the official launch date.
Rockstar said in a statement: "We are in the process of investigating early 'sales' to determine how and why that is occurring."
The company had previously requested online retailers not to ship the title until today (Monday, September 16th).
GTA 5 is the latest in Rockstar's hugely popular Grand Theft Auto video game franchise, which has sold more than 125 million copies worldwide to date.