LONDON – A lawyer whose client accuses author Dan Brown of stealing ideas for his mega-selling conspiracy thriller “The Da Vinci Code” said Monday the novelist’s testimony should be treated with “deep suspicion.”

Making his closing submission at the end of a three-week trial, attorney Jonathan Rayner James also asked why Brown’s wife, Blythe – who did a large chunk of the research for the novel – was not called as a witness in the copyright-infringement case.

Michael Baigent and Richard Leigh are suing “Da Vinci Code” publisher Random House, claiming Brown’s book “appropriated the architecture” of their 1982 nonfiction book, “The Holy Blood and the Holy Grail.”

Both books explore theories – dismissed by theologians – that Jesus married Mary Magdalene, the couple had a child and the bloodline survives.

If Baigent and Leigh succeed in securing an injunction to bar the use of their material, they could hold up the scheduled May 19 film release of “The Da Vinci Code,” starring Tom Hanks and Audrey Tautou.

Sony Pictures says it plans to release the film as currently scheduled.

In a written statement handed to the court Monday, Rayner James said Brown copied from “The Holy Blood and the Holy Grail” but acknowledged he may have done so “unwittingly because of the research materials supplied by Blythe Brown.”

“His evidence should be approached with deep suspicion,” the lawyer said.

“He had almost no recollection of matters that related to timing. He would struggle to recall a year, was rarely able to recall a month. His general attitude in cross-examination was uncooperative,” Rayner James said, referring to Brown’s three days of testimony last week.

Brown, who lives in New Hampshire, was not in court Monday.

Rayner James said evidence from Blythe Brown would have been of “fundamental importance to this case.”