I would like to know
What is the name of the mental facility?
Did he admit himself voluntarily to the mental facility or was admitted by a doctor?
What date did he admit himself?
What date did he leave the facility?
Did he at anytime check himself out the facilty on the dates relevant to CL going missing
What reason did he give for feeling suicidal
Did he kill CL and then immediately go the the facility because of what he had done (murdered someone else again and buried/disposed of the body)
I believe that when establishing an Alibi or checking a suspect police would want those questions answered.
If I wanted to believe the Halliwell theory. I would be asking:
Why commit a crime outside of Wiltshire?
Why travel for almost 4 hours to abduct?
Why go to a city without a red light district but pass many on way including Leeds?
Could it equally have been an unknown abductor in that area?
Why return to North Yorkshire even though he had connections in South Yorkshire?
Why turn his back on all other girls walking home from night clubs that night / early morning?
Why were Becky's cardigan and Sians boots the only items recovered from the pond and none of other named missing persons?
Were the items recovered from the pond lost property left in his taxi(s) or did he have a washing line fetish?
What we must remember is this.
If he did it-Which he didn't, then he is safely tucked up inside for the rest of his days and so job done-result and all other females safe from him.
If he didn't do it and we keep saying he did then we let the evils of the hook.
I'm done on Halliwell. Why give him even more credit for what he already did.