Mark Conditt, the Texas man who carried out a three-week bombing spree, made a 25-minute video "confession" on his phone, which was recovered after he blew himself up on Wednesday.

As police searched for a motive behind the attacks, a picture was starting to emerge of the 23-year-old suspect, who was described as "polite" and a "deep thinker" who "really just wanted to tell the truth".

Mark Conditt, from the Austin suburb of Pflugerville, died in the early hours of Wednesday, killing himself in his car as a SWAT team closed in on him in the town of Round Rock, 20 miles from Austin.

Commenting on the video confession, Austin Police Chief Brian Manley said: "He does not at all mention anything about terrorism, nor does he mention anything about hate, but instead it is the outcry of a very challenged young man, talking about challenges in his personal life."

Police said they had learnt of his identity in the previous 24 hours, when he had dropped off a package at a FedEx in Austin and was caught on CCTV. They then obtained his Google search records, and found suspicious activity.