Austin bomber's sinister alias reportedly used to ship explosives

The Austin bomber suspect believed to be behind the bombings that killed two and injured at least four others reportedly used a sinister alias to ship two packages containing bombs, according to law enforcement sources.

Mark Conditt, 23, is said to have used the name “Kelly Killmore” to send the parcels through FedEx shortly after 7:30 pm on Sunday, US broadcaster ABC reported.

FedEx Corp said on Wednesday "key evidence" it provided to law enforcement officials led to the identification of the Texas bombing suspect, according to an internal FedEx memo seen by Reuters.

"FedEx was able to provide law enforcement with key evidence leading to the identification of the suspect responsible for the bombing because of our advanced security capabilities and the vigilance of our team members," FedEx Chief Operations Officer David Bronczek said in the memo.

CCTV images obtained by ABC reportedly shows the suspect entering a FedEx location in Texas on Sunday wearing a blonde wig and baseball cap and dropping off two parcels.

They remained in the shipping system until one exploded on a conveyer belt at a FedEx facility in Schertz, Texas.

Following the explosion, police were able to make ground in their investigation and track the suspect.

After a brief pursuit on Wednesday, Conditt blew himself up on the side of a highway as police closed in on him, authorities say.

"The suspect is deceased and has significant injuries from a blast that occurred from detonating a bomb inside his vehicle," Austin Police Chief Brian Manley told reporters near the scene.

FBI's reminder to step up parcel security

Separately, the Federal Bureau of Investigation has reached out to package handling companies to remind carriers about established protocols for handling suspicious packages and mail safety, FBI spokeswoman Lindsay Ram said by email.

"The FBI continues to advise the public to remain vigilant and not touch, move or handle any suspicious packages or unknown packages and to call law enforcement when they believe they have received a suspicious package," Ms Ram said.

FedEx was screening every package at the Texas facility where a parcel exploded on Tuesday, and will also X-ray entire trailers of packages at its sorting facility outside Austin, as well as those originating from or sent to the Austin area, a FedEx manager said.

The FedEx employee was not authorized to speak on the record. The source does not work at the sorting facility but was briefed on the situation.

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Packages will likely be delayed by a day or two at the facility, and FedEx was re-routing thousands of other packages to its hub in Houston each day through the end of the week to avoid further delays, the employee said.

FedEx spokesman Jim McCluskey declined to comment on package screening and on the evidence FedEx provided authorities.

FedEx and other package delivery companies collect a vast amount of data on packages in their systems, such as the location where the package was picked up by the driver and the time.

The industry delivers around 40 million parcels in the United States each day and checking a large portion of that volume on a regular basis would paralyze operations and increase costs, said Satish Jindel, a founder of the delivery company that became FedEx Ground and now president of ShipMatrix, which tracks on-time shipments.

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"It would shut the economy down," Jindel said.

Like FedEx, UPS shipping terms and conditions allow employees to open and inspect packages.

The FedEx employee said in-bound international shipments are screened by x-ray or bomb-sniffing dogs, though it is possible the Texas blast could lead to more security measures domestically.

UPS spokesman Glenn Zaccara said the world's largest package delivery company constantly evaluates and adjusts its security measures, but does not discuss them in order to maintain their effectiveness.