In a high-profile murder case that grows colder by the day, Yale and local authorities now hope a lot more money and a little more attention could make the difference.

The problem, experts say, is that a reward is rarely effective in drawing out reluctant witnesses. Even if it were, would someone who refused to come forward for $50,000 two years ago suddenly decide that three times that amount is enough of an incentive?

And like nearly every bit of information revealed over the past 28 months, Tuesday’s announcement that Yale has tripled the reward for information relating to the Suzanne Jovin ’99 murder investigation added to the size of the puzzle without filling in any of the pieces.

First, there is the brown van that witnesses reportedly saw at the crime scene on the night of the murder. New Haven Police Chief Melvin H. Wearing said the driver might have seen something important, but would not reveal any more information about it, leaving many to ask why it took over two years for even the existence of the van to be revealed to the public.

Then there is the status of James Van de Velde ’82, a former Yale lecturer and Jovin’s thesis adviser, who remains a suspect in the case because, Wearing said Tuesday, police cannot rule him out.

Van de Velde originally became a suspect because the “facts and circumstances led detectives to suspect him,” Wearing said.

Yet Van de Velde passed a rigorous government screening process when his security clearance came up for review last year. He and his lawyer, David Grudberg ’82, said there has never been a single shred of evidence to link him to the crime. He has even fired back at some of his accusers, filing lawsuits against Quinnipiac University and the Hartford Courant for libel.

If those two issues were not enough for a single press conference, there remains the matter of the reward itself. Yale added $100,000 to the $50,000 state reward Gov. John Rowland offered two years ago.

Former New Haven Police Chief Nicholas Pastore, a fellow at the Criminal Justice Policy Foundation, said rewards are a common, but rarely successful way to try to “warm up” cold cases.

“In all my time, I can’t think of a case that was solved because of a reward aspect of it,” Pastore said.

Hartford State’s Attorney James Thomas said he has been involved in very few cases in which rewards were actually given out after a conviction, but he said the announcement itself can generate enough attention to make it worthwhile.

“It’s the offer of the reward that generates the interest in the case,” Thomas said. “A person may come forward with information about the case that doesn’t qualify them for the reward but does aid in the investigation.”

So the “why” of the reward seems relatively clear: to get the word out that the case remains open and that investigators are desperate for any available information.

But the reason for doing it Tuesday, rather than two months or a year ago, is not. It is this question, in fact, that remains the most puzzling aspect of the announcement to many.