He is, and Martin is inside the black fence.
Look at the second image of the guy bent over. On the right, the image without the three text boxes, zoom in.
The guy with the white shirt and cap is on this side of the fence. You can see the first rail post to his left. It merges with a person's legs so you see feet at the base, but you can find the post outline higher up. The person is behind the rail which is tough to make out at the feet. Then there's the guy bent over. The next person with the blue jacket with white markings is on the other side of the railing and has their hands resting on the rail. Just past that person you can see one more vertical fence bar just below the red shirt.
In the first image of the guy bent over, the line points to something that is not the fence and it is confusing. But you can see that diagonal striped thing just in front of Martin in the second image of the bent guy. Beyond that you can see the back railing of the fence.
I might be a bit late here, but, no he's not
Look at the man standing with the boy on his shoulders in the third photo down on the left. In front of him is an Asian looking woman with red shoes
Now look at what she is standing on... its red brick.
Look at the photo of the blast stain in the top left photo, its red brick, right?
Now, go back to the third photo down, look to the Asian woman's right and find a man in a tan jacket wearing glasses. Next to her is a woman in a purple jacket (in the 4th photo down she is talking on a cellphone) look next to her in both photos. The ground is grey (concrete?) not red brick.
Now look at the top photo again, the ground transitions from red brick to grey a lot further from the blast site than it does in all the photos with the people in them.
If the media are saying that the bag over which the person is bent, is the bomb that left the black stain, then its one of the worst pieces of photo interpretation I have seen.
The black object in the lower photos is clearly not the iron fence in the top photo.