Petit was beaten with a baseball bat as he, his wife and two daughters were tied up in their Cheshire home. Petit managed to escape to a neighbor's house for help, but his wife was strangled and the girls died of smoke inhalation after the house was set on fire.
When Petit testified in the trial of Komisarjevsky co-defendant Steven Hayes, he referred to testimony of earlier witnesses and corrected what others had said, Komisarjevsky's attorneys said.
Prosecutors do not have any real interest in Petit's presence in court "aside from the potential to unduly influence jurors seated in close proximity to the Petit posse," defense attorneys wrote in their motion last month, referring to Petit and his supporters.
Komisarjevsky's attorneys also said Petit is known to most jurors and has advocated for four years for their client's conviction and execution.
Todd Bussert, one of Komisarjevsky's attorneys, said Monday that Petit had a "quest for vengeance" that could have kept him out of the courtroom for the entire trial.
Blue said crime victims have the right to attend trials unless a court determines their testimony will be affected if they hear the testimony of other witnesses. He said he could not make such a finding in this case.
Prosecutors said Petit has given consistent testimony, would not be affected by other witnesses and has a right to attend the trial as a victim.
Michelle Cruz, the state's victim advocate, also spoke on behalf of Petit. She said the examples cited by defense lawyers were only instances of Petit not being able to recall things other witnesses had testified to and there was no proof his testimony was changed as a result of listening to other witnesses.
"It's definitely a victory for crime victims," Cruz said.
Petit said outside of court he was happy with the ruling.
"We just want justice," Petit said.
Komisarjevsky's trial starts next month. Hayes was convicted last year and is on death row.