The assault and robbery happened near the church's parking lot.
The parish priest immediately alerted his congregation which helped spread the word quickly throughout this neighborhood.
At 5:30 a.m. Sunday Jenny Quan heard someone screaming for help outside her window.
Police say a 35-year-old woman was sexually assaulted near 60th Street and 6th Avenue in Sunset Park.
Police say a man fondled her, stole her purse and then took off running.
Sunset Park resident Bettina Delprete can't believe this happened so close to her home.
"5:30 on a Sunday morning, not that many people. There are some who go to work. I just hope they catch the person," Delprete said.
The suspect's description is vague; an Asian man in his 20s.
Anyone with information is asked to call police.
There have been a string of sexual assaults in the Park Slope area.
Police believe this attack is not related to those.