Richard Poplawski, convicted of killing three Pittsburgh police officers 15 years ago, claimed in a recent court filing that the jurors who sentenced him to death may have been unduly influenced during a field trip they took during an off day in the trial.

Poplawski, 38, is asking an Allegheny County Common Pleas judge to provide additional funding so that investigators can question the Dauphin County jurors who heard the case.

The court has so far prohibited the defense team from contacting the jurors at all, the filing said.

The panel, chosen from the Harrisburg area because of pre-trial publicity, voted for the death penalty in 2011 after finding that Poplawski ambushed and killed Officers Eric G. Kelly, Stephen J. Mayhle and Paul J. Sciullo II on April 4, 2009, at his home in Pittsburgh’s Stanton Heights neighborhood. They were responding to a domestic dispute between Poplawski and his mother.

The state Supreme Court upheld Poplawski’s punishment on direct appeal in 2015.

He is now pursuing an appeal under the Post Conviction Relief Act, which provides a way for defendants to challenge their convictions.

The case, now assigned to Judge Kevin G. Sasinoski, is scheduled for a hearing on Nov. 18.

In a Sept. 27 motion, Poplawski’s appellate attorneys, Douglas Sughrue and Corrie Woods, asked for additional funding and time to file an amended petition.

The motion notes that Vickie Piontkowski — who is studying Poplawski’s background to find evidence that might mitigate his culpability — has conducted a significant portion of her work but still needs funding for 500 more hours over another one to two years to complete her investigation.

Piontkowski wrote in a court filing that the mitigation investigation done for Poplawski prior to trial was inadequate.

For example, she said it did not include include interviews with his mother’s mental health providers, people he served with during basic traning in the Marines and other relatives.

As part of the defense’s ongoing investigation, Poplawski’s attorneys also said that they have obtained information that jurors in his case may have been subjected to external influence.

Although the jury was sequestered throughout the trial at the DoubleTree Hotel in Pittsburgh — and kept under guard by the Allegheny County Sheriff’s office — the motion notes that on an off day, deputies took them on a field trip.

On that day, June 26, 2011, jurors visited several locations, including houses of worship on the North Side, Downtown and in the Hill District. They also went through the South Side and Mt. Washington, visited the Pittsburgh Steelers’ offices and what was then Heinz Field, and took an after-hours tour of the Heinz History Center.

The defense motion notes that public consciousness and comment on Poplawski’s trial was at a “fever pitch, and almost exclusively against him.”

The filing notes a letter to the editor in the Pittsburgh Tribune-Review in which the writer said Poplawski deserved the death penalty. It also mentions a sign in a South Side bar: “Free Fries if Poplawski Fries.”

“It is unknown whether the jurors’ routes on their ‘field trip’ passed by the sign urging petitioner’s death,” the motion said.

Poplawski is currently being housed at the State Correctional Institution at Somerset.