Can't really tell but the Cardiff's dead guy seems to have a tattoo on his right arm.

[link to i.dailymail.co.uk]

The mosque attacker has a noticeable tattoo in his right arm, but his right forearm is covered by the crowd.

[link to postimg.org (secure)]

Would be great if any of you lazy-ass morons start doing some detective work for a change, instead of waiting all the answers spoonfed to you.