People with relatives buried at Burr Oak Cemetery outside Chicago are learning DNA may not help them find their loved ones.

Authorities say the piles of bones and deteriorated records may make identifying many remains impossible.

Officials estimate that at least 300 of 100,000 graves were tampered with at Burr Oak. Exhumed bodies were dumped in a deserted field the size of four square blocks.

Forensic experts say viable DNA can be extracted from many of the skulls, teeth and large bones. But investigators warn it may not do much good because in order to find matches, scientists must test relatives from all of those buried at Burr Oak.

And experts say it may be impossible to match bones to specific people and return complete remains to a single grave.