iPhone died at 30% battery and wont start again?

For a while I have been using "Mobile Power Station" (an external battery charger) with my iPhone 3GS 32GB.

A couple of days ago I used the phone, connected to the mobile power station, just surfing the web. Then, suddenly, the LEDs on the mobile powerstation started flashing. The iPhone LCD flashed one time and then the phone went dead.

And now, it's still dead. I mean really dead, dead, dead. It won't power on, no charge in neither wall or computer.

I tried soft reset (HOME+Power) and connecting to Itunes in DFU-mode, nothing works! :(

It seems to be a hardware error, but what?

Burned circuits?

When I check the liquid submersion indicator in the dock connector it looks red, just like it suffered a water damage. But I know that my phone never suffered a water damage so I suppose the indicator went red just by humidity.

So my question is, what happend to my phone? what do I need to do to repair it?

Thank you!