Norah McClintock 
In Too Deep [PDF ebook] 

Robyn should be having the time of her life. She has a great summer job, and it’s just a boat ride away from her friend Morgan’s lakeside house. But she misses her boyfriend, Nick. Suddenly Nick appears in town-on a dangerous mission. He promised a friend he’d investigate a local suicide. Did Alex Richmond drown himself? Or was he killed because he knew too much? Robyn intends to find out-whether or not Nick wants her help.