London ? Arguments closed in “The Da Vinci Code” copyright case with the lawyer for the men suing the publisher of the blockbuster novel suggesting that author Dan Brown’s testimony was unreliable and questioning why his wife, who helped research the best seller, did not testify.

Jonathan Rayner James, whose clients say Brown stole their ideas for his huge best seller, said Monday that the novelist’s testimony should be treated with “deep suspicion.”

He also asked why Brown’s wife, Blythe, who did much of the research for the book, 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.

Judge Peter Smith said he would give his verdict in the case before the current court term ends April 13.

In a written statement handed to the court Monday, Rayner James said Brown had 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 testimony during three days on the stand last week.

Brown was not in court Monday.

Rayner James said evidence from Blythe Brown would have been of “fundamental importance to this case.” He claimed she would have been able to confirm the extent to which “The Da Vinci Code” relied on Baigent’s and Leigh’s work.

Dan Brown knew “little about what she did,” Rayner James said.

Brown has acknowledged that he and Blythe read “The Holy Blood and the Holy Grail” while researching “The Da Vinci Code,” but said they also used 38 other books and hundreds of documents, and that the British authors’ book was not crucial to their work.

Under cross-examination by Baldwin earlier in the trial, Baigent conceded that several of the plaintiffs’ key allegations were wrong, including the claim that Brown used “all the same historical conjecture” as “The Holy Blood and the Holy Grail.”

Rayner James acknowledged that his client, Baigent, had been “a poor witness.”

“He was overawed by the circumstances and agreed almost without exception (with) anything said by the judge,” the lawyer said.