Three decades ago, Boston's city government bulldozed buildings Pamela Saucer-Richardson's owned on Erie Street in Dorchester and took control of the land. Her father had about $5,000 in unpaid property taxes. That land has sat vacant since. Now the city wants to give it to nonprofits — but no one has reached out to Saucer Richardson's family, she said. GBH's Paul Singer explores the history behind Boston's empty lots.