A man convicted of murder in Philadelphia and sentenced to life without parole will have another chance to argue that a police officer who testified in his case and whose niece he dated was biased against him, a Third Circuit panel found in a split decision.

The majority said in an opinion filed Friday that Keith Whitmore should have the chance to show that Officer Dennis Johnson, a key witness for the state, was biased against him and that Whitmore's trial attorney never investigated this alleged bias.

"Whitmore's allegations, if true, show ineffective assistance. But neither the state nor the federal district court gave Whitmore a chance to prove those allegations," the majority said, reversing the district court's decision and requiring an evidentiary hearing.

Whitmore wrote in an affidavit that "although he informed his trial counsel about Johnson's harassing, intimidating, and threatening him because of his relationship with Johnson's niece, counsel failed to investigate this bias," the majority said.

During the trial, when Johnson was being questioned, Whitmore's attorney asked for a sidebar after Johnson testified that he knew Whitmore from the neighborhood, according to the majority. The attorney was concerned that Johnson's testimony could lead to discussions of his past arrests of Whitmore, the majority said.

Whitmore said the fact that his attorney didn't even know whether Johnson had arrested him in the past showed "that counsel did so little investigation into Johnson's prior relationship with Whitmore" even when the attorney specifically assured Whitmore he was looking into their relationship.

Whitmore argued that there was no proof in the record that his attorney ever "conducted any investigation whatsoever, and he asserts that counsel never did," the majority said.

While there were other witnesses who linked Whitmore to shooting Andrew Sliwinski and killing Scott Sliwinski, those witnesses were minors and offered conflicting testimony describing the murder weapon, with one unsure if Whitmore was the perpetrator, the majority said. Johnson was the only person whose testimony linked Whitmore to the Sliwinski shooting by connecting him, via a later incident, to the specific murder weapon the state said was used in the killing, according to the majority. 

Though the state tried to argue that Whitmore's lawyer may have strategically decided not to ask Johnson about his prior relationship with Whitmore for fear of bringing up Whitmore's narcotics involvement, the majority said "nothing in the record shows that Johnson previously arrested Whitmore and, if so, whether the arrest led to a conviction. Moreover, a prior arrest for narcotics would have only a minimal effect, if any, on the jury's perception of Whitmore, who [the minor witnesses] already described as a drug dealer."

As a result of all this, the majority said Whitmore should have a chance to prove his claims and that the lower court made a mistake in not permitting it.

In his dissent, U.S. Circuit Judge Peter J. Phipps called the majority's reasoning "flawed."

"It was objectively reasonable for Whitmore's counsel not to investigate Johnson's bias more thoroughly because the introduction of any evidence of Johnson's bias at trial would be highly likely to backfire," Judge Phipps wrote, explaining that if Johnson were allowed to say he didn't like Whitmore because he was a drug dealer with bad character, that could harm Whitmore.

Judge Phipps said it was "objectively reasonable" for Whitmore's attorney to decide not to lead Johnson down this road "to avoid placing evidence of a criminal defendant's bad character or criminal history before the jury."

Additionally, Judge Phipps said, this is why Whitmore had not been able to show prejudice — since it was not clear what the outcome of investigating Johnson's bias or introducing it to a jury might have been.

"Further investigation alone or even further investigation coupled with a successful impeachment of Johnson would not have a 'reasonable probability' of changing the outcome of the trial," Judge Phipps wrote.

Representatives for the parties did not immediately respond to requests for comments Monday.

U.S. Circuit Judges Cheryl Ann Krause, Peter J. Phipps and D. Michael Fisher sat on the panel for the Third Circuit.

Whitmore is represented by Rosemary Auge of the Federal Community Defender Office for the Eastern District of Pennsylvania.

The commonwealth is represented by Peter F. Andrews, David Napiorski, and Anthony Salzetta from the Philadelphia County Office of the District Attorney.

The case is Whitmore v. Superintendent, Forest SCI, case number 22-2237, in the U.S. Court of Appeals for the Third Circuit.

--Editing by Linda Voorhis.