Following your lead in regards to alcohol....
As
@Mel 1303 related, the bill was $40.00- which seems to be about 28.00 US dollars and notes that this number implies one diner.
The men were in good physical condiyion, young and large. Even if all spent on alcohol, $28.00- or even, $40.00 US dollars was not likely to get the assailant(s) drunk. Then factor in that if this apparently Muslim owned restaurant served alcohol, it was probably of the more sedate beer and wine variety and not the say.... Happy Hour!! $5.00 "Jack 'n Coke" type.
The totality of your and
@Mel 1303 's observations could support the following:
- 3 co workers, team mates, possibly military are in town for a night on the town. They go to a bar- probably of the $5.00 Happy Hour drinks variety to start the evening off right. They start to get drunk. But.. perhaps this bar does not have food? Or, maybe they do, but only salty snacks?
- One of the crew is hungry and leaves the bar in search of something more to eat. Wanders to the Curry restaurant. Orders food for himself, maybe has two more beers to put himself over the top.
- His friends arrive and encourage him to skip the bill- or he skipped it on his own initiative. A fatal confrontation occurs.....
Regardless of whose idea to skip out it was, it could have been, as you implied, alcohol fueled. If it was alcohol fueled, the trio was probably went some where a little bit more wilder first to "tank up", then one went to the restaurant.
Was this possible initial bar with in walking distance?