Does an attorney by the name of Francis Onegwa exist in Lagos, Nigeria?

I'm going to go out on a limb and guess that you've received an email
from this person asking you for money.

If that's the case, it's a scam.

Please see the web page of fraudaid.com:
http://www.fraudaid.com/ScamSpeak/Nigerian/nigerian_scam_letters.htm

search terms: nigerian scam spam
://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=nigerian+scam+spam+&btnG=Google+Search

I hope this helps.

David,
       I hope you have not fallen for the Nigerian Letter Scam now 
"sold"  through the internet. I get around 10 of these a week on
average from various people claiming plane crash victims with no will,
diamond mine oversupplying or double invoices, bank officials with
access to accounts of dead people etc  etc all of which involve many
millions of dollars (from $5 to $35 million in my emails) that simply
require your bank account number to which the funds are transferred
from which you will recieve a good percentage.  Of course when you
notify with interest you will find that there is just one person that
has to be bribed to get the paperwork underway for whic h will only
cost you a trifling $2000 and then after that a very unexpected 
official barrier requiring another $5000 etc  etc until they have
milked you  fora s much as  they can before you wake up that you are a
victim of a con. To see who has been wiped clean of money by these
people just type in " Nigerian Letter Scam" on the GOOGLE search
engine and various stories about who lost how much and when and why
will come up
 As a sneak preview you may like to know that an American whose name
provided gave one of these low life people about $500,000  over a year
or more before he woke up that he was a sucker. Another in my country,
Australia, gave a similar amount. according to the website, this con
is now around the third largest income provider for the country with
the $$ now in the billions that people have sent back to Nigeria.

 The one I like is from the woman who claims her father died as bank
manager of some bank secretly advising her of $20M he had stashed away
that  belonged to no-one, or could not be traced.  She starts off with
" For Gods sake help me"

This scam has even resulted in murder in at least one case: "According
to the U.S. Secret Service, these 4-1-9 scams, named after the section
of the Nigerian penal code that addresses these types of fraud
schemes, are a serious threat to Americans. One part of the scheme
involves bringing the "mark" to Nigeria to receive the funds promised.
This often leads to kidnapping, threats of violence and has, on at
least one occasion, led to murder."
http://www.zdnet.com/products/stories/reviews/0,4161,2609884,00.html 
This site has a lot more information on the matter, and several links
to further details.