A Chicago woman was struck and killed Thursday by a chunk of stone that fell off a gargoyle statue on a 140-year-old church.

Sarah Bean, a 34-year-old mother of two, was walking on a sidewalk three stories beneath Second Presbyterian Church when a chunk broke off the gargoyle and struck Bean on the head, the Chicago Tribune reported.

The noon tragedy happened in front of Bean's fiancé, Lance Johnson, who was out for a lunch date with Bean before the start of her shift at Lurie Children's Hospital. Johnson was seen placing his hands on either side of Bean's head while screaming, witnesses told the newspaper.

Witnesses said Bean was killed instantly.

"I saw that crack on her head and thought, 'She's definitely dead,' " Broderick Adams, who saw the incident from his apartment window across the street, told the Tribune.

The chunk apparently broke off when a piece of decorative metal on the church's façade came loose and fell on top of a gargoyle sticking out from the church's southeast tower.

According to the city's Buildings Department, the South Michigan Avenue church, built in 1874, received a series of violations between 2007 and 2011. Some were for failure to make sure the stairs inside were safe and failure to clear building exits.

Other violations were for "fractures, washed out mortar at various locations, spalling (flaking) stone at various locations at (north, south, east and west) tower elevations," reads one 2010 citation obtained by the newspaper.

But the Gothic-looking church passed inspections for 2012 and 2013, the same year it was designated a national landmark.

Reverend Robert Reynolds, executive presbyter at the Presbytery of Chicago, extended his prayers for "the family and friends of the woman who died."

The reverend said church congregations are responsible for maintaining their buildings' upkeep. He said he was "not aware of any immediate structural issues they were addressing," the Tribune reported.

Police have launched an investigation into Bean's death.