The lawyer for the owner of the Center City building that collapsed and killed six people inside a Salvation Army thrift store called for a mistrial Thursday and for the Philadelphia judge to step down, accusing her of favoring the victims in the civil trial.

The motion by veteran lawyer Richard A. Sprague, representing New York real estate speculator Richard Basciano, came one day after a key expert witness called by Sprague unexpectedly gave testimony adverse to Basciano.

Sprague blamed Common Pleas Court Judge M. Teresa Sarmina for letting plaintiffs' lawyer Robert J. Mongeluzzi elicit the testimony during Wednesday's cross-examination of structural engineer Najib Abboud.

Sprague said Sarmina had compounded the problem by questioning Abboud and allowing him to expand his responses to Mongeluzzi.

"The overall conduct of this trial has shown that your honor has made an unbelievable number of inconsistent rulings favoring the plaintiffs over the defense," Sprague said in an often-acrimonious session before the jury entered court.

The 91-year-old Sprague called for an immediate halt to the trial, which began Sept. 19, and for the Pennsylvania Supreme Court to appoint another judge for a retrial.

"I don't want to retry this case, but I think we've reached the point where, regardless, there will be a retrial," Sprague added.

Sarmina denied Sprague's mistrial motion and his demand that she recuse herself.

"A higher court will make a reading of whether my rulings were appropriate or not," Sarmina said.

Sprague's motion consumed much of Thursday morning before Abboud returned to the witness stand. A Sprague associate, Peter A. Greiner, told Sarmina that the Basciano defense would finish Friday. If that happens, lawyers for the Salvation Army would begin calling witnesses in defense of the charity.

In addition to the 91-year-old Basciano and his STB Investments Corp., the Salvation Army is being sued for allegedly keeping warnings of the dangerous demolition next door from the thrift store's employees and customers.

Abboud, 54, a principal with the New York-based Weidlinger Associates, had won acclaim for his postmortem probe of why the World Trade Center towers collapsed after the Sept. 11, 2001, terrorist attacks.

Questioned by Greiner, Abboud countered earlier testimony by plaintiffs' experts that demolition of Basciano's Hoagie City building was so slipshod it was a public danger as early as May 15.

Abboud testified that his own computer modeling of the June 5, 2013, collapse showed that the building - and the unbraced wall that toppled and crushed the thrift store at 22nd and Market Streets - could have withstood sustained 40 mph winds until demolition started June 5.

"It would not have collapsed, barring some significant external force being applied," Abboud testified.

That force, lawyers for Basciano and the Salvation Army contend, was Sean Benschop, operator of the 36,000-pound excavator working on the building.

Basciano's lawyers have argued that he is being blamed for the acts of incompetent demolition workers recommended to him by Center City architect Plato A. Marinakos Jr., who was hired by STB, which owned the site, to monitor demolition.

Sarmina asked Abboud whether the building might have collapsed on its own in the next few days. Abboud testified that the building was stable as long as demolition did not resume.

Mongeluzzi then posed a hypothetical question: What would Abboud, as a licensed professional structural engineer, have done had he been on the scene before demolition resumed June 5, 2013?

Abboud tried to avoid answering until finally, over Greiner's objections, Sarmina told him to answer.

"My recommendation would be to evacuate the site" and call the Department of Licenses and Inspections, Abboud replied, calling it a "life-safety issue."

"No lives needed to be lost," Abboud told the jury. "Up to that morning, this tragedy was preventable."

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