Is McNair murder book author credible?

A grand jury is slated to hear a former Nashville police officer explain why former Tennessee Titans quarterback Steve McNair’s murder case should be reopened, ESPN.com’s Liz Merrill reports.

From her story:

Rob McKinney, a defense attorney in Nashville, said it's unusual for the grand jury to hold such a hearing.

"I don't want to say it's unheard of," McKinney said. "But it's extremely rare."

As an outsider looking in, I’m surprised this is happening and certainly curious what comes out of it.

Vincent Hill, the former Nashville police office who’s presenting the information Friday, was part of this Dateline NBC piece last August. When I saw it back then, I had some major questions about his credibility and qualifications and lined up with this Jim Wyatt review of the piece.

Hill's recently self-published "Playbook to a Murder," outlines holes in the official case and his belief that Sahel Kazemi, who was ruled to have killed McNair and then herself, was not the shooter.

Perhaps there are lingering questions as the July 4 anniversary of McNair’s slaying approaches. Is Hill the guy who can pose them and offer plausible alternative answers?

I’m anxious to see if this grand jury thinks so.