What/who else would there have been without JM's lies ? Because there was no forensic evidence of any kind in which to pin the murders on Jeremy.
JM was coerced by the police,particularly SJ,to go as a prosecution witness,with a sweetner of £25,000 to go with it pending a conviction.
I bet that JM was very uncomfortable with this " arrangement" and it was only the thought of the financial gain that kept her going.
Without the encouragement from SJ,she'd have fallen flat on her face.
EVERYONE likes money,and JM was no different,being in the position at the time to like it even more after splitting up with Jeremy, so looked upon it as a means to an end and also as a form of " compensation " against her loss/dream of becoming mistress of WHF one day.
If only we'd been privy to her 32 statements,eh ?