THIS IS A story and a lesson. The story is of a killer who would have hated to know his brutal life helped to inspire a Philadelphia artist to become a crime fighter. The lesson is on the value of the death penalty.

True justice never did catch up with multiple murderer John Martini.

He died of natural causes.

He was pronounced dead at 2:21 a.m. on Sept. 10 in the infirmary at New Jersey State Prison in Trenton. He was 79.

He had been sentenced to death for the murder of Irving Flax, a New Jersey businessman, in 1990 and was on death row until 2007, when the state abolished the death penalty.

"I don't want him to die of natural causes," Marilyn Flax said of Martini. "My husband didn't."

Martini told a reporter the death of Irving Flax was an accident. He laughed when he said it.

Flax was kidnapped in 1989 by Martini and was killed after Marilyn Flax paid him $25,000 in ransom. Flax was "accidentally" shot three times in the head by Martini, an accident, of course, that removed from this earth the man who could have identified him.

It was the same way Anna Duvall was killed by Martini in Philadelphia in 1977, shot three times in the head.

She was found in a field near International Airport. When her body reached the morgue, damage from the wounds and decomposition had made identification seemingly impossible.

Philadelphia Medical Examiner Halbert Fillinger was standing nearby when artist Frank Bender came through for anatomy studies.

Bender looked down at the body of a woman on a table. No one should have been able to see a recognizable human face. An artist trained at the Pennsylvania Academy of Fine Arts could.

"I know what she looks like," he said.

Fillinger believed him.

It took eight hours for Bender to create a sculpture that wound up as a hand-painted fiberglass bust, a photo of which was put on a flyer that was spotted by a policeman. It matched an actual photo of Anna Duval on a missing person's report.

"I saw every feature of her face," Bender said, "and how the form of one part of her face flowed into all of the other forms." It was the first sculpture he ever completed, even though he'd been trained in the techniques.

Police investigators learned Martini had bilked Anna Duval of $35,000 in a land deal and lured her to Philadelphia with a promise the debt would be settled.

It turned out to be in the way he usually chose to settle things.

Martini had to be transported from New Jersey State Prison

to Philadelphia for a trial in which he was convicted in 1997 of Duval's murder.

He was also convicted of two other murders in Arizona. These convictions and the one in the Duval case came after the death sentence for the Flax murder. Since you can't execute anybody more than once, life sentences were imposed for the last three murders.

Martini was also a prime suspect in at least two other killings.

A term used by war correspondents comes up when reporting on Martini's life and times:

Body count.

Medical Examiner Fillinger was so impressed with Bender's work on Duval that he taught him about forensics. "When he started," Bender said, "I didn't even know what the word meant."

Bender doesn't keep a list, but since Anna Duval, he's worked on the busts of probably 40 or more victims or perpetrators of crimes. He helped solve most of those cases.

The most famous was John List, an accountant who resolved mounting financial problems by shooting and killing his mother, wife and three children. He left the bodies lined up in their Westfield, N.J., home and disappeared for 18 years.

"America's Most Wanted" asked Bender in 1989 to provide it with a bust of List that would show what he looked like after all that time.

Bender has to work most often with skulls from skeletal remains, using his talents and intuition as an artist and what he's learned from criminal psychologists, anthropologists, forensic dentists and police experts to help identify subjects.

This was different. All he had to work with were old photos of List to produce a bust that aged the killer by 18 years.

When the bust was shown on TV, a woman from Colorado called and said List, using an assumed name, was a former neighbor of hers.

Eleven days later, the FBI tracked him down in his new home in Virginia.

List got life in prison.

Besides "America's Most Wanted," Bender's story has appeared on "48 Hours," Court TV, "60 Minutes," and on programs in Germany and Japan. It's also been told on the pages of Time, Newsweek, Reader's Digest, Esquire and GQ.

Bender would still be working in his studio on South Street even if he had never turned to forensic art. He could have sketched and painted and maybe turned to sculpture, anyway.

Fine art.

As it is, there are only a handful of forensic artists in the world working at the level of Frank Bender. And he could be best of all.

Incredibly, a case could be made that without a murderer named John Martini, there never would have been a forensic artist named Frank Bender.

Larry McMullen wrote a column for the Daily News for 20 years. E-mail him