Norton Shores Police Chief Daniel Shaw said the search turned up no new clues.
Heeringa is believed to have been abducted from the Exxon station on Sternberg Road between 10:50 and 11:15 p.m. Friday, April 26. Around 7:30 a.m. the following morning a caller reported hearing gunshots near P.J. Hoffmaster State Park.
Later, when a person found sunglasses that resembled Heeringa's, police decided to search the area. Chief Shaw said the sunglasses were later determined not to be Heeringa's.
Purse Contained $400
Shaw also said that Saturday was the beginning of turkey season in the area, which could explain the gunshots.
Meanwhile, police released a report revealing that Heeringa's purse, which was left in the gas station when she vanished, contained $400 in cash. They also said the cash in the station's cash register was undisturbed.
Police have released a sketch of a man they want to question in connection with Heeringa's disappearance.
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Photo: Family Photo