Beyond a "who done it," the question before a Dallas judge Monday will be "who has it?"

As in, the "sniper's perch" at the Texas School Book Depository – the southeast corner window through which Lee Harvey Oswald is accused of firing on President John F. Kennedy.

Caruth Byrd says he inherited that sixth-floor window in 1986 from his father, Col. D. Harold Byrd, former owner of the downtown Dallas building.

Aubrey Mayhew says he had it removed from the property in the early 1970s.

Both say they have the real deal. And their long-standing dispute over a potentially profitable piece of history is coming to a head in the 191st State District Court.

Byrd, 67, of Van, Texas, has sued Mayhew, 81, of Nashville, Tenn., asking the court to declare Byrd the owner of the true window.

The suit says Byrd, who put his window up for auction two years ago, is unable to get fair market value because of Mayhew's conflicting claim.

And he wants Judge Gena Slaughter to either order Mayhew to return any window he has from the school book depository, "if such window exists," or enter a court judgment against him for the window's value.

"He'll pay hell getting that," Mayhew said of his window, which he says includes the wooden casement and glass – evidence he won't be bringing to court. "I'll have some very nice pictures," he said Friday.

He also won't be bringing a lawyer despite the judge's suggestion at a recent hearing that he get one. "I don't have the money to pay them," he said.

Yet Mayhew says he will press his claim. "He doesn't have the window," he said of his challenger.

Byrd and his lawyer, Joel Elliott, were unavailable for comment at week's end.

But their lawsuit says Byrd's father had "what was believed to be" the Oswald window removed six weeks after the Nov. 22, 1963, assassination.

Byrd inherited the window after his father's death, according to the suit, and has retained possession except for the 11-plus years it was displayed at The Sixth Floor Museum at Dealey Plaza.

The elder Byrd purchased the building in 1939. Mayhew, a collector of Kennedy memorabilia, bought the property from him in 1970, intending to establish a museum. The colonel financed the sale and took the property back in 1973 after Mayhew defaulted.

Mayhew said Friday that before losing the building, he hired two carpenters to remove and replace the window. A handwritten testament letter, dated Aug. 9, 1971, and signed by the pair, describes the work.

Carpenter Leo Fernes recalled Friday how he and his boss, Andy Balcom, followed Mayhew to the sixth floor of the building.

"He says, 'I want you to take that window out,' and then we went to the back of the building, and he showed us one he wanted to replace it with," he said.

They worked at night, attracting attention from people below, completing the job in about three hours, said Fernes, who now lives near Tulsa, Okla. "I wasn't too sure about the situation. It didn't seem like a real up-and-up thing," he said.

More than 37 years later, he said his memory of the work has faded. "I don't know if it was exactly the [southeast] corner or the next one in."

In an interview two years ago, Mayhew recalled the work: "We took the window down to the loading dock, and I paid those guys, and they left, and on Monday, I called the storage place to come and pick it up. It was stored for 20 years over there. It was treated with absolute care."

Mayhew also said Friday, as he has before, that a building tenant told him that Byrd's workers removed the wrong window. He plans to offer in court a letter signed by O.V. Campbell, former owner of the school book business, which seeks to "clear up the questions and doubt surrounding the sixth-floor window."

The trial comes two years after the contestants tried to sell their windows. Byrd's offering drew a bogus bid of $3,001,501, a deal that quickly dissolved when the winning bidder didn't have the money.

The day after Byrd relisted his window, Mayhew offered his on eBay as well with a minimum opening bid of $999,999.99, receiving no takers.

Mayhew said Friday that he never intended to sell the window, which he also listed on his own Web site for $20 million. The idea behind advertising the window was to publicize the conflicting ownership claims, confound bidders and discourage a sale, said his son, Parris Mayhew, who said he suggested the postings.

"If a window sold for in the millions, everybody would think it was legitimate," he said.

In 1995, as a prelude to the Sixth Floor exhibit, Byrd dramatically unveiled his window for elected officials and the Dallas County Historical Foundation.

"My dad had this window in his home for years and years," he said. "When he passed away in 1986, I took it to my ranch in Van, Texas. I kept it behind a chest of drawers. ... I thought and thought about what to do with it. I've had offers for a lot of money for it, but I decided the best thing to do was to bring it home where it belongs."

Does the display, which ended in September 2006, amount to the museum's endorsement of the Byrd window? Museum officials wouldn't discuss the case Friday.

"We can't comment on pending litigation," museum spokeswoman Christina Carneal said.

Staff writer Michael E. Young contributed to this report.