AUBURN – The trial of a Sabattus man who shot his ex-girlfriend in the head during a bitter custody dispute was tainted even before testimony began because of improper conduct by a grand jury member, the defense contends.

A female grand jury member and her boyfriend visited the crime scene at 81 Roberts Road in Sabattus in what amounted to an independent investigation, said Leonard Sharon, lawyer for convicted murderer Daniel Roberts.

The boyfriend, who later blogged about the crime scene visit, insisted it happened several months before the grand jury was convened to consider charges against Roberts.

A motion filed by Sharon on Friday seeks to have the indictment thrown out, effectively vacating Roberts’ murder conviction two weeks ago.

Prosecutors contend Roberts lured Melissa Mendoza, who was unarmed, to his garage, where he shot her in the back of the head on Aug. 15, 2005. At the time, the two were embroiled in a fight over custody of their 2-year-old daughter, Savanna.

The defense contended Roberts fired in self-defense after Mendoza, angry and unpredictable, arrived in the garage holding a stolen handgun.

After Roberts was found guilty of murder, Sharon said, someone told him that a grand juror’s boyfriend had blogged about their investigation on the Sun Journal newspaper’s Web site in response to a story about the case.

The blogger posted messages twice on Feb. 7. He said he and his girlfriend had gone for a walk on Roberts Road, which led to the murder scene.

The blogger identified as “Louie” wrote that there was a photo sensor on a telephone pole that would have alerted Roberts that Mendoza was pulling into the driveway. “There is no doubt in my mind he hid behind the door and shot her in the head,” the blogger wrote.

A man who identified himself as Louie the blogger told The Associated Press on Tuesday that he and his girlfriend and her daughter were out for a walk when the daughter pointed out the driveway that led to Roberts’ home.

“I wasn’t out investigating Danny Roberts’ property,” Louie said.