Even Afghan Taliban is also employing suicide bombers.
TTP has only recently gained its foothold in Punjab and their old form was/is still active in NWFP which has it’s close proximity with Afghanistan.In anyway it is simple to think that they have got links with Afghan Taliban.Infact,that would be their most convenient and easy source of arms and resource supplies.
You may recall last year’s Lahore Police Academy attack and a few instances those followed ,where Afghan nationals had been involved in TTP attacks.