Try this link for the main problem in the Delta states . . .
Movement for the Emancipation of the Niger Delta - Wikipedia, the free encyclopedia.
The real problem in Lagos is armed street robbery exacerbated by the fact that traffic is pretty much static from 0630hrs til 1930hrs so if you were robbed in your vehicle you dont have the option of driving away from the danger.
The only advice that can be given (apart from personal and vehicle security) is dont carry too much money or valuables and give them what they want and you should walk away pretty much unscathed
Bear in mind that there are no weapons permits issued to non locals in Nigeria!!
AJ