The owners of a stolen $60m art collection which, it later emerged, was not insured claim that the investigating Sheriff's department "reeks corruption and incompetence."
The accusation comes after Commander Mike Richards made the owners, Benjamin Amadio and Dr Ralph Kennaugh of Monterey Pebble Beach, suspects in the puzzling theft.
Commander Richards has voiced suspicions that the theft might be a hoax.
Meanwhile, Amadio and Kennaugh have reportedly offered a $1m reward for the collection, reports the news website SFist.
The burgled collection included works by Pollock, Miró, Rembrandt, Matisse and Van Gogh. It was originally described as worth $27m, but the estimate is has since risen to $60-80m.
Amadio and Kennaugh have argued that the authorities are turning on them because they bungled the investigation from the start.
Vicki St John, the pair's lawyer, had previously complained about the length of time taken by police to investigate the scene of the theft.
However, police suspicions have been raised due to an alleged lack of evidence that the paintings were actually owned by the pair in the first place.
The ex-partner of Vicki St John, David St John, has now confirmed that he visited the residence prior to the burglary and saw both the paintings and their proof of ownership.
But the Sheriff's department remains unimpressed.
Usually, art collectors keep deeds or data demonstrating ownership of the pieces. The collectors contend that this was stolen along with the art works. But it is unusual for these documents to be stored with the pieces rather than elsewhere, usually with a lawyer.
The revelation that the one-of-a-kind pieces were uninsured and kept in an unsecured home has also raised eyebrows at the Sheriff's Department.
Vicki St John intends to hold a press conference on Friday, at which she will list the stolen works and display their images.
As part of their investigation, police suggested that Amadio and Kennaugh take a lie detector test, but the pair refused.