What's up (what was up)

--はどうした・---はどうなっている

1.

I heard a big explosion. I called the local police station to find out what was up, but the line was busy.

2.

Then I saw the guy holding the gun and I realized what was up: it was a bank robbery!

3.

The soldiers saw two guys "hanging out" and they stopped to see what was up. "They looked
and decided that something was not right with this situation," the colonel said.

(click here for original context)

4.

Nice to have you back. I noticed your absence, but sometimes you stay quiet so I didn't know
what was up!

(click here for original context)

5.

Does anyone know what's up with his hair? Why did he get a mohawk haircut?!!