It will be ok if his conclusion is “I didn’t find her in the river”. And very difficult indeed if it is “I didn’t find her in the river therefore she didn’t fall in the river therefore the phone is a decoy therefore a 3rd party is involved”. I think I can guess which way he’ll goPeter said he plans to search for a couple more days until he is certain she is not in there. He said with the way the tide goes she will naturally flow up and down the river but it was impossible for her to have reached the sea by this time. Interesting listening to him, but it will put the police in a very difficult position if he completes his search and makes his conclusion.