There are several ways to look at the Manorville carpenter whose murder trial begins Wednesday morning.

To Suffolk police and prosecutors, John Bittrolff, 50, is a retired serial killer.

But to his attorney, family and neighbors, Bittrolff is a hardworking family man popular in his community who was never in trouble before his arrest in 2014.

Bittrolff is charged with two counts of second-degree murder in the deaths of Rita Tangredi, 31, of East Patchogue, on Nov. 2, 1993, and Colleen McNamee, 20, of Holbrook, on Jan. 30, 1994, based on what prosecutors say is a DNA link between him and semen found on Tangredi and McNamee, who both worked as prostitutes.

He is also suspected — but not charged — in the Nov. 20, 1993, death of Sandra Costilla, 28.

And some of the many amateur sleuths obsessed with the bodies found over the years in and around Gilgo Beach have suspected him in those deaths too, although law enforcement has emphatically ruled him out.

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The trial that is about to begin in Riverhead before state Supreme Court Justice Richard Ambro is expected to last about 10 weeks. Before jury selection began, Bittrolff rejected a plea offer from Ambro of 20 years to life in prison. If convicted of both charges, he faces a maximum of 50 years to life.

“There’s going to be some pretty graphic evidence that’s going to be presented,” Assistant District Attorney Robert Biancavilla warned potential jurors during jury selection last month. “You’re going to hear a lot of heart-wrenching testimony in this case. You have two young girls, who despite the life they chose, have families.”

Defense attorney William Keahon of Hauppauge asked potential jurors to be wary of detectives trying to sell more than they have. “They are going to be trying to convince you of something,” he said. “Use logic and your common sense to decide if they’re right.”

Biancavilla has said the links between the deaths of Tangredi, McNamee and Costilla have always been obvious. All three women were found badly beaten and strangled, and posed identically, with their legs spread and arms over their heads. All three had wood chips on or near their bodies — significant because of Bittrolff’s profession, Biancavilla has said.

Costilla’s body was mutilated, unlike the other two, and none of Bittrolff’s DNA was found on her body.

But Keahon has said the DNA link has limited meaning. Sexual contact alone is not evidence of murder, and he’s said there is no other evidence of any kind of his client’s guilt.

Further, DNA from numerous men was found on the bodies and clothing of Tangredi and McNamee, Keahon has said. Any of them could have been the killer or killers, he said.

Keahon also pointed to a list of more than 75 suspects in the deaths over the past two decades, which includes at least two Suffolk police officers.