In their December 24, 1990 issue (page 22), US News & World Report informed their readers that well informed sources on the Soviet Pacific island of Sakhalin had confirmed “that Soviet authorities did, in fact, retrieve the black box with the flight data…. The sources add that Soviet officials admit having used decoy pinging devices to send false signals to American and Japanese search vessels as they scoured international waters off the Sakhalin coast looking for the box.”
The veracity of these “informed sources” was corroborated by the subsequent release of high level Soviet communications by Boris Yeltsin in 1992. (Copies available here: Memos)
Then on September 1, 2003, the Deputy Director of the Russian Federation State Archives of Recent History confirmed the Soviet pretense of searching for the KAL 007 airplane while they knew all along where the plane was. Ruse Details
Further information continues to dribble out. Most recently, Leonid Antseliovich, a former designer of the Soviet Sukhoi 15 TM interceptor which was used to down KAL 007 and a current resident of the US, pointed Bert Schlossberg to the August 31, 2005, edition of the influential Russian newspaper Moscowsky Komsomolets in which Russian military historian Alexander Kolesnikov quotes one of the key players in the downing of KAL 007 - General Ivan Tretyak. General Tretyak was the Commander of the Far East Military District in 1983, later to be promoted to commander of the Far East Theater of Operations. In addition to his military command, General Tretyak held a high political position - member of the Central Committee of the CPSU - and as such was privy to many of the decisions made of national importance. Here is military historian Alexander Kolesnikov's quote from General Tretyak -
We had decided to provide the Americans with a "false point of falling", and indicated this location by the presence of our ships. They "took the bait". They started for there with ships and helicopters. It so happened, that one helicopter fell in this area... (verified by Admiral Walter Piotti, Commander of Task Force 71 of the U.S. 7th Fleet in his After Action Report).
At the following link you can read the latest information on the known survivors including Larry McDonald, a sitting US Representative at the time the plane was captured. The last information to reach the west on his location was in 1995. Surviving Passengers