The five men are not accused of stealing the painting
A senior solicitor has told a court he found it "very surprising" a contract over a stolen painting contained a provision police were not to be told.
Malcolm McPherson said he had received a call that the painting had been recovered from a law firm's office and a partner had been arrested.
Calum Jones was held after Leonardo da Vinci's Madonna of the Yarnwinder was found at the office.
He is one of five men who deny seeking £4.25m for the painting's return.
The masterpiece was taken from Drumlanrig Castle in 2003.
Mr McPherson, the senior Scottish partner in HBJ Gateley Wareing, said he was with a client in Edinburgh when he was phoned by lawyer David Boyce on 4 October 2007.
Mr McPherson told the High Court in Edinburgh: "He told me that the picture had been found in the office and that Calum Jones had been arrested."
He said he was informed that police had come to the office and that Mr Jones had been "trying to repatriate the picture".
Mr McPherson said HBJ Gateley Wareing had been involved in the takeover of another law firm, Boyds, where Mr Boyce and Mr Jones worked in August 2007.
Advocate depute Simon di Rollo asked Mr McPherson if he was aware of the "so-called transaction" over the painting during the takeover and he replied: "Never at any time."
Mr McPherson said he became aware a document had been prepared concerning the return of the picture with a clause that said "fundamentally nobody would tell the police or any other law enforcement agency".
The prosecutor asked Mr McPherson if he found it surprising as a lawyer that there was a proposition that the police were not to be told. He said: "I think it's very surprising."
In further evidence antiques dealer James Tierney told the court that Marshall Ronald, 53, had acted for him in compensation dealings with Liverpool council and he contacted Mr Ronald to demand when the money was going to be paid.
Mr Tierney said a meeting about the money was eventually set up with Mr Ronald. Mr Tierney told the court: "He said he had used it for this deal he had done with this painting."
On trial along with Mr Jones, 45, from Renfrewshire, and Mr Boyce, 63, from Lanarkshire, are Mr Ronald, 53, Robert Graham, 57, and John Doyle, 61, all from Lancashire.
A further charge alleges that they attempted to defeat the ends of justice by requiring an undercover officer to sign an agreement that police would not be notified.
They are not accused of stealing the painting and deny conspiring to extort £4.25m or attempting to extort the money.
The trial continues.