What’s the matter with Massachusetts?

Two violent cases. Two district attorneys who went on to bigger things — one Martha Coakley, to become Massachusetts attorney general and then to an unsuccessful run, as a Democrat, for the U.S. Senate seat once occupied by Ted Kennedy; the other DA Bill Delahunt, since 1996 a Democratic congressman from Massachusetts.

There were many reasons Coakley lost that Senate race — among them a case from 2005 when, as Middlesex County district attorney, she delayed in prosecuting a policeman who was alleged to have sodomized his 23-month-old niece with a hot object, probably a curling iron. It was left to Coakley’s successor to prosecute, and the man is now serving two life terms. Rumors, never proven, abounded that the ex-cop’s father had political ties to Coakley.

Now comes the astonishing case of Amy Bishop, who last week shot six colleagues during a faculty meeting at the University of Alabama-Huntsville — three died. In 1986, when the Harvard Ph.D. was 19 and living in her family home in Braintree, Mass., she shot to death her 18-year-old brother, Seth Bishop. The Norfolk County DA, the aforementioned Delahunt — then in the middle of his almost 20-year term as DA — didn’t press charges.

The relatives and colleagues of those six victims must wish that he had.

Traveling in Israel when the story broke of his long-ago involvement, Delahunt, through a spokesman, said he had no clear memory of the case. Some of the records are said to be missing. A report of the investigation carried out at the time by the state police pointed to Seth Bishop’s death as a tragic accident.

Unfortunately, no successor to Delahunt ever reopened the case.

There were only two references that I could find that raise suspicions that there might have been some sort of political reason why officials at the time didn’t take a closer enough look at the older sister’s involvement.

On Monday night’s “O’Reilly Factor,” in a conversation with Fox anchor Megyn Kelly, Bill O’Reilly, said, “And the press reports that Delahunt didn’t go after Amy Bishop back then because of some political reason. That her family was wired in the state.”

In Sunday’s Boston Herald, reporters O’Ryan Johnson and Jessica Fargen wrote that Bishop “was freed decades ago after a politically derailed investigation into her fatal shooting of her own brother.” They add, “According to [Paul] Frazier [current Braintree Police Chief], then-Chief John Polio ordered cops to release Bishop — whose mother, Judith Bishop, Frazier said was a public official sitting on the Personnel Committee.”

We will see what comes of that, but a few things are certain — that case will be re-examined, and Amy Bishop, now 42, will likely spend the rest of her life in prison — if she’s lucky. Alabama has the death penalty. If Delahunt runs for his eighth term in 2010, the name Amy Bishop will often be on the lips of his opponent(s).

Postscript — Amy Bishop’s Who’s Who of American Women entry is full of fascinating information (in retrospect). The youngest of her four children, her only son, is named Seth Bishop, presumably in memory of her brother. Under civic-military involvement, she lists participation in MoveOn.org, Huntsville, 2005-06. She also lists professional involvement with NASA.