PLEASANTON — It started when a local woman answered an Instagram ad touting a free book about investing in the stock market, and it ended four months later, when she called police to report she’d been scammed out of $1 million, authorities said. The plight of this Pleasanton woman is only the latest internet scam to affect a Tri-Valley resident. The woman reportedly believed she was going to learn from a professor who could predict stock market trends, and that she’d eventually join an investment project. She was told to pay the couriers foreign currency with the expectation of receiving returns in American dollars at a later date. Police say the couriers sometimes used rideshare services to pick up cash from her Pleasanton home and that she believed she was talking to the stock market wizard’s assistant over social media.