The visitors were unannounced and unexpected. At 6 a.m. on Jan. 18, Paul Burrell, the late Princess Diana's unflappable butler, woke up to find seven Scotland Yard detectives at his door, demanding to question him about items allegedly missing from her estate. Burrell, a family friend says, "went to pieces."

Over the next 12 hours, the officers reportedly ripped up floorboards in the Cheshire home that Burrell, 42, shares with his wife, Maria, and their two sons, then interrogated him about a jewel-encrusted model of an Arab dhow that purportedly went on sale after Diana's death.

The investigation into the dhow–which for years occupied a ledge in Diana's Kensington Palace apartment–had already led to the questioning last November of Harold Brown, another former butler to Diana, and London fine art dealer Jan Havlik. But the interrogation of Burrell, whom Diana called "my rock" and who spurned million-dollar offers to write a tell-all book after her 1997 death, came as a particular shock. Did the butler do it? By law, British police can't comment. But Burrell's father, Graham, 66, defends his son, who is free pending another date with the police. "He swears on his life he knows nothing about that ship," says Burrell Sr. "He would not betray anyone's trust for any amount of money." The Palace has withheld comment, but a spokesman for Diana's brother Earl Spencer says, "We are very surprised."