By Brad Segall

WARMINSTER, Pa. (CBS) — Authorities in Bucks County are not saying when they plan to release more details about who fired the fatal shot that killed an 89-year-old woman during a shootout in Warminster last week.

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Nevertheless, officials say, additional charges are likely for the man who allegedly opened fire on police.

Bucks County district attorney David Heckler says he’s taking his time with the investigation and waiting for all the reports from his detectives and ballistics information from Montgomery County detective John Finor, who is a firearms expert (see related story).

But Heckler does say that regardless of whether police or Andrew Cairns fired the shot that killed Marie Zienkewicz, he’s confident that Cairns will face more serious charges.

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“Whether that it is a general count of murder, whether it’s first-degree murder, whether it’s something less than that is going to need to have the complete investigation done,” he told KYW Newsradio.

Cairns is being held in lieu of $10 million bail (see related story), currently charged with attempted homicide, aggravated assault, and numerous other offenses for putting the lives of six Warminster cops in danger.

The elderly woman, who lived below Cairns at the “Jefferson on the Creek” apartment complex, was killed by a single bullet wound.

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