It was January 2012, a month before the start of the child endangerment trial of Msgr. William J. Lynn, and retired Philadelphia Police Detective Joseph Walsh was called back to work by the District Attorney's Office to prep a key prosecution witness.

Instead, Walsh told a Philadelphia judge Friday, the veteran detective found himself unable to get the 23-year-old witness to explain numerous inconsistencies in his story of being molested by two priests and a parochial-school teacher in a Northeast parish in 1998 and 1999.

"You've got to have an answer," Walsh said he told the accuser. "He would just stare down at the table."

Walsh said the accuser said he was sexually molested by two priests at St. Jerome's parish. One of the alleged assaults lasted five hours after he was an altar server at the 6:15 a.m. Mass, he said.

But Walsh said there was no record of the accuser serving those Masses, including on his mother's home calendar, where she recorded her sons' various church assignments.

The accuser also said he was a member of the parish bell choir and the "bell crew" although three teachers involved with that program could not corroborate that.

"I said, 'You got to straighten this out before you go into court and testify,' " Walsh testified.

The Inquirer's policy is not to identify sexual abuse victims or accusers.

The accuser did testify at Lynn's 2012 trial, in which the archdiocesan official was convicted of child endangerment for his supervisory role over deviant priests.

Lynn, the first church official convicted in the clergy sex-abuse scandal, served 33 months of a three-to-six-year prison term before he was released in August after a state appeals court granted a new trial.

The question now before Common Pleas Court Judge Gwendolyn N. Bright is whether prosecutors should have ever let the accuser testify.

Also at issue is whether prosecutors should now be barred for misconduct from retrying the 66-year-old Lynn because they did not heed Walsh's warnings.

Bright said she will announce her decision on the defense motion to dismiss the case March 1.

Defense attorney Thomas A. Bergstrom argued that prosecutors should have informed him of Walsh's doubts about the accuser's credibility before the 2012 trial.

Walsh testified that several times in late 2011 he told Assistant District Attorney Mariana Sorensen about his doubts: "The inconsistencies in my mind were just so great."

Walsh said Sorensen replied, "I believe him" and complained that "you're killing my case."

Walsh, however, said he could not recall whether he warned Sorensen after the preparation session and before the start of trial.

Assistant District Attorney Patrick Blessington said Sorensen, who left the District Attorney's Office shortly after the 2012 trial, has denied making the comments to Walsh.

Sorensen, who managed the evidence going before the county grand jury investigating archdiocesan clergy child sex abuse, did not testify Friday.

Blessington did not call any witnesses and said Walsh's testimony was irrelevant because he could not say if he warned Sorensen about the accuser immediately before trial.

Blessington argued that Walsh's prep session with the accuser was not part of the investigation that led to Lynn's arrest but role-playing to prepare the accuser for hostile questioning by defense lawyers.

Blessington accused Bergstrom of exaggerating Walsh's testimony to get Friday's hearing and asked the judge to admonish the defense lawyer.

Bergstrom, however, argued that Sorensen herself should have confronted the accuser about the purported inconsistencies.

"She had this case locked up until the good detective unlocked it," Bergstrom told Bright.

"As a prosecutor, if you believe a witness is lying, you have no reason to put him on the witness stand," Bergstrom added.

215-854-2985 @joeslobo