Murder Riddles

The Climbing Trip

A man went with his wife on holiday, to a nice secluded area in Reunion Island. There, he decided to go on a climbing trip, his wife decided to go as well.
While they were about to zip line (27 meters above the ground) over a lake full of crocodiles, the wife set herself up, and while she wasn't looking, the man quickly cut her harness, and gave her a mighty shove. She fell down into the lake with a splash, which followed with a cloud of blood, surfacing in the lake. The man, didn't feel guilt. He knew she had been cheating on him with three other guys, and she didn't appreciate him enough. So, she had to go. He pulled his best surprised face, and called for the life guards. They came running, but when they saw nothing was to be done, they called the police and the ambulance, to escort the man back to his hotel.
A few days after this had happened, the police came into his house.
The man looked surprised, and asked if they wanted to interrogate him a fifth time.
"Oh, we don't have to interrogate you," the officer said, as another fastened the mans hands in handcuffs, and shoved him into a police car.
"What proof could you possible have?!" the man shouted.
"Your travel agent called. And she had undeniable proof." the officer said, slamming the car door shut.

What did the estate agent know?
Comment if you know, vote if you liked!