
1) public place: spike his drink, get him semi-conscious into a toilet stall and slash his wrists and throat.
hard not to be seen and very messy.
chucking him off a bridge is very appealing but tricky to arrange, and not necessarily fatal.
2) his place: drug him, chuck him in a hot bath and slit him up (as above).
takes a fair bit of work to get into his place - probably can't break and enter and overpower him, and I'm not psychotic enough to 'befriend' him.
also I don't have ready access to anything powerful enough to knock him out, nor poison him without the taste being noticeable.
so I'm just going to settle for secretly dosing him with laxatives instead