Questions surround memorial interpreter

The Deaf Federation of South Africa wants to know who vetted the sign language interpreter for Nelson Mandela's memorial.

he seems to be gesturing with authority

signing to keep pace with the speaker

"side by side, dreaming the same dream"

" Reporter: but this sign language

interpreter at Nelson Mandela's

memorial service was a fake, according to

the deaf federation of south Africa

They claim he's had no formal training

the signs he's making are notTused in south Africa

signs language, and he never used

facial expressions, a key part of signing

The federations says that there are established signs

for famous people in south America

-Reporter "Formal president, Thabo Mbeki..."

But one expert says the signed name

for Mbeki never appeared

The deaf community in south Africa is outraged

"Because he's a fake interpreter and he is

just been signing arbitrary signs"

A deaf member of south Africa's parliament

tweeted during the ceremony:

"He's just making up, get him out of TV sight"

That lawmaker is an alum of

this place, Gallaudet University in

Washington, the world's only liberate arts

college for the hard of hearing

Melanie Metzger says she doesn't know

south Africa sign language, but there are

universal indications of something wrong here.

"you see the repetitive movements here and here,

There's a repeated gesture, but the speaker

is not repeating the spoken message

so you can see just by that the

interpretation is not accurately equivalent

Reporter: " if this man was a fake,

was he a security risk?

He stood inches from president Obama

and other world leaders.

The white house seemed uncomfortable talking about it

"I would refer to the south African government

about who that person was and what their responsibilities were

Reporter: "Who is he? It's a mistery

The south African government won't comment

saying it's investigating

Former secret service agent, Larry Johnson says the host

organization provides names of everyone

in the inner parameter to the secret service

48 hours in advance so, names, backgrounds

can be checked but

"Being bad at your job is not a concern of the secret service,

The concerns are, is he someone that shouldn't be there because

he has bad intentions. he is known the law enforcement,he is a security risk.

Johnson says iy looks to him like those red flags did not

show up in the background. So did the secret service vet him?

The agency tells us that agreed-upon security measures

between the secret service and south african security officials

were in place during the ceremony

The secret service says that the host organizing the commitee was

responsible for the selection of the interpreters

Wolf, as we told you, the south African government for the

moment not commiting their investigations

There are reports, there are plenty of them,

this man has been observed doing this elsewhere in the past.

That's right, The Guardian newspaper says that

members of south Africa's deaf community

have raised concerns before about this interpreter

he's apparently been used that sum of stages

by the african national congress

now the ANC has told us they have used

him in the past but they didn not hire him for this