My mother-in-law, Claire, is determined to spend the rest of her days on Long Island. While most of the family migrated south to Georgia and Florida, she remained in her house on Peconic Bay.

I can’t say as I blame her. It’s idyllic there. The bay is on one side and she’s surrounded on the other three by a nature preserve teeming with deer and fox. Southampton, with its trendy shopping and exclusive restaurants, is only a few miles to the east. In the opposite direction is Riverhead, its roads lined with big box stores and outlet malls. She could take classes, perform volunteer work and play bridge to her heart’s content. Move? Never.

Three years ago things began to change. Claire had several bad falls. Well past 80, she became more forgetful, losing keys and neglecting to turn off the oven. The dings and dents on her Volvo’s bumpers told the rest of the story. If she was going to stay in her home she would need help.

My brother-in-law, Ron, was the only family member living nearby. The work of hiring and managing a caregiver fell upon him. He did everything right. He advertised and interviewed applicants. He checked references. He kept at it until he found the perfect person. We’ll call her Jane.

Jane was bubbly and funny and energetic. She lived nearby and could spend part of each day with Claire. She took her shopping and to medical appointments. Claire reveled in the attention.

She gave Claire a reason to get up each morning. We saw an immediate improvement. She was more alert and seemed happier. It was wonderful.

Thinking back, there were some hints that all was not quite right. Jane quickly insinuated herself into the family, calling Claire, "Mom" and Ron and my husband "bro." She would bring her young children over to play in Claire’s yard and encouraged them to treat Claire as a surrogate grandmother. It creeped me out a little, but I told myself I was being petty and jealous.

It made sense to give Jane a credit card. After all, she was doing a lot of Claire’s shopping and picking up prescriptions. We made a big mistake when we failed to insist on accountability in the form of detailed receipts from the start.

Each month the credit card purchases mounted. Mostly there were increased grocery purchases but the prescription charges increased as well. Later we found out that Jane was getting pain medication prescribed for Claire by asserting that she was experiencing severe back pain.

Since Jane was the person who accompanied her to medical appointments, the physicians knew her and took her at her word.

Strong pain medication was prescribed and filled but we’ve never seen any indication that Claire actually took the pills. We’ve never found a bottle of them in the house. Indications are they went home with Jane and from there, who knows?

As Ron’s suspicions grew, the grocery store proved to be an ally. I had no idea that they could retrieve every sale charged to Claire’s card. There it was in black and white. There were purchases for pork chops, beer, huge sacks of dog food. Charged to a teetotaling Kosher grandmother with a cat but no dog.

My brother-in-law acted quickly. Jane was fired and he made a police report. While never admitting any wrongdoing, she eventually made some restitution in order to avoid prosecution.

Echoes of Jane still reverberate from time to time. Recently Claire called to ask me if she had given me or her granddaughters a particular piece of gold jewelry. She hadn’t. I suspect I know who has it.

We’ve all been affected by this experience. Each of us felt duped and taken in, none more so than Claire. She was genuinely fond of Jane, and this betrayal is never far from her thoughts.

There’s a new caregiver. We’ve learned a lot from the Jane debacle. Expectations are fully outlined and receipts are routinely checked. Things have gone well for the last year.

What makes this story so sad is that it’s so common.

As the sandwich generation struggles to care for aging parents while maintaining careers and raising children of their own, there’s frequently a need to hire outside help.

All I can say is, be careful. Be very, very careful.