By Steve Tawa

PHILADELPHIA (CBS) — The Market Street building collapse civil trial has resumed, with a former top city official on the stand. It’s in its 11th week, and could last another month.

In the days before the deadly June 2013 collapse that crushed the Salvation Army thrift store at 22nd and Market Streets, an aide to the developer sent the Army several emails warning of the danger of an imminent collapse.

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Six people were killed and 13 were injured when unbraced walls on a building being demolished next door gave way.

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Former Deputy Mayor for Economic Development Alan Greenberger was copied on some those emails, but on the stand, Greenberger testified he never saw them and never responded.

Now, a professor a Drexel University, Greenberger recalled getting hundreds, often more than 700 emails a week in his capacity as Deputy Mayor, from various agencies and outside interests doing business with the city. But he never opened up those so-called “warning emails” that Thomas Simmonds, who worked for developer Richard Basciano, sent to the Salvation Army.

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Earlier in the trial, Simmonds acknowledged to jurors that his warnings about the “threat to life and limb” were efforts to apply pressure on the Salvation Army to move the project along more quickly. The Salvation Army refused to give demolition crews next door access to its roof. It also rejected Basciano’s attempt to have the Army move its Thrift Store to the next block, in a swap of properties.