logs for system shutdown

I am working on a SUN T2000 machine with Solaris 10 running on it. When I checked the system this morning, I found it to be turned off. The lastreboot command showed that the system had been shut down the previous night.

I want to find out how the system was shut down. I have run hardware health checks on the system and found no problem. Are there any logs from which I can find out how the system was shut down (Manually from switch or by giving the init 5 command).

The /var/adm messages and the syslog dont have any useful info.

any crash dumps? you confirm the messages file have nothing? dont you at least see the bootup msgs? what happened before that?anything shown? or were there any activities, like large file transfer occuring? who were logged in to the system during that time?

what shell are you running? say you run bash, you can check history to see if anyone initiated a shutdown command.