Found some more details online
Mary Anne Wesolowski went missing from 44 Hudson Ave., on August 18th. Mary Anne was told to go back to Haviland Cove, to tell her mom's boyfriend, Chuck Phillips, to come home. Earlier that morning, Mary Anne, her brother Paul, and one of her girlfriends were at the beach at Haviland Cove, and saw Chuck with another woman. When they told their mom, she told Mary Anne to go back and tell Chuck to come home. MaryAnne went to the corner of Hudson Ave. and Spring St, (road configuration has changed since Urban Renewal in 1971) where Her brother Paul asked her if he could go with her. She told him to stay home, she would be back soon. NO ONE has seen her since...
This puts a different spin on things. Did they even question the stepfather?