From a thief’s point of view, the place had a lot of potential.

It was big, with lots of room to work. Rows and rows of cars that almost certainly contained valuables left behind by their owners, more so than on a normal city street. What was more, the cars were almost guaranteed to be unattended for at least two or three hours while the owners were away.

The location’s only drawback: it was the parking lot for visitors to Rikers Island. At the other end of a long bridge sat the huge jail complex that held the inmates these drivers were visiting. That must deter many potential thieves.

But not all.

It was Oct. 7, a Sunday, typically a busy day when family members who cannot come on a weekday find time to visit.

One of them was Ailsa Williams, 39. She was going to see her son, whose name and crime she declined to share in an interview. She had been visiting for months and was prepared for the long day ahead, beginning with this parking lot.