If law enforcement is handling the investigation by giving all the information they find over to Kaine Horman, then they cannot be trusted and heads should roll - starting with the sheriff at the next election. They need to protect the information relevant to finding Kyron Horman as well as maintain the integrity of their department. Releasing any information they have gathered during an investigation to aid Kaine Horman's divorce against his wife is opening themselves up to being deposed because Terri Horman has the right to the evidence being used against her.
For the sheriff's department to release information to Kaine Horman they know will be "leaked" to the public opens the sheriff department up in a defamation lawsuit Terri's attorneys should file and it causes a lack of public trust in their department. Terri has the right to see the information law enforcement has given to Kaine since Kaine stated in court documents (that he immediately leaked to the media) law enforcement told him Terri tried to hire his friend's landscaper buddy to kill him. Terri has the right to the evidence in order to defend herself against the allegations. Terri's attorneys could get get all of the evidence by subpoena that law enforcement allegedly gave to Kaine if they filed defamation lawsuits against him and/or the sheriff's department.
If Kaine is lying and claiming LE is giving him information when they are not, Kaine should be arrested for interfering with a police investigation. He could also be charged in lying to the court (via sworn affidavit) If the information he is leaking to the media is "legitimate", then he is definitely interfering with the investigation to find his son by "leaking" the information. Either way, his actions are grounds for his arrest. He seems to forget this isn't just about his divorce and defaming his wife but it's about finding Kyron.