I thought she was simply so confident that she'd done the perfect crime and would get away with it(see her early TV interviews) that she was kind of regretting not being able to boast that she had been the one to punish TA for his sins, let alone shove her and TA's sordid relationship in all TA's marriageable choices' faces ... so felt the need to soak up every minute of pain she could wring from his family and friends to feed her compulsion for that fleeting "ultimate gratification" she craved, as she so succinctly put it in her blog on May 10, 2008.
I wondered also if she went to the funeral to try to get attention as his "girlfriend." Kind of in the way a widow gets so much attention, love, and support when her husband dies, or even more so when he is murdered. But she was too narcissistic to realize that many people at the funeral already had pegged her in their minds as the murderer, rather than as the sympathetic character of brokenhearted girlfriend.
Or maybe she wanted to be there to hear if the police had any suspects, or to glean any information which could be helpful to her in the event she was accused of the crime.
Or she could have gone for the reasons already stated. Much as arsonists like to come back and watch the mayhem they have created, she may well have wanted to relish in the drama and heartache she'd left in her wake.