Fiona watched Montana approach her mother. Actually, she wasn't that suspicious of him. It's just that her little sister didn't come home or even return her text messages. Moreover, Montana was also someone who saw Tessa before. In a flurry, Fiona's mind had gone defensive.
He said 'don't think ill of me', but she didn't know why he would be helping out a stranger… when she actually needed some. His timing was strange. She was just someone he met in the gym. If he wasn't someone like Griffin, then he had no reason to show up at her doorstep.
However, she was shocked when she found out that her mother knew Noah. It's just that… her mother blurted that very accusation that made Fiona not report to the police. Her mother was suspecting people without proof! That was dangerous if her mother was wrong.