Bet he was drunk and some sort of argument or altercation happened once they got to her house, probably some sort of rejection or being confronted on his drunkenness or turned down. This was NOT what he had envisioned for the night to end and in a buzzed, pissed off rage, killed her. That will sober you up REAL quick and then go into "cover your a$$ mode." The whole cut up the body thing was his plan to get away with it. Dump in garbage cans etc. etc. By this time he knew what he had done and what he was doing. Possibly regretful but more terrified of getting caught. The guy didn't exactly have a normal life and wouldn't be too familiar with garbage schedules and recycle vs garbage cans. Plus he was exhausted, hung over and spent.. forgot the saw, purse, ID, tickets.. didn't know the recycle schedule...Dump the car, crash on the curb...