Blacksburg, Virginia, April 22 (AP): The Virginia Tech killer went to the Internet less than a month before last Monday’s massacre to get ammunition clips that fit one of the two handguns he used in the rampage, an eBay spokesman said.

The eBay account demonstrates the prime role computer forensics and other digital information have played in the investigation into the worst mass shooting in modern US history. When the subject of an investigation is a loner like Seung-Hui Cho, experts say his computers and cell phone can be a rich source of information.

The online auction site lists the purchase date of the empty clips as March 22, about three weeks before the attack in which Cho, 23, killed 32 people and himself.

eBay spokesman Hani Durzy said the purchase of the clips from a Web vendor based in Idaho was legal and that the company has cooperated with authorities. “In looking at his activity on the site, we can confirm that at no point that he used eBay to purchase any guns and ammunition,” Durzy said yesterday. “It is strongly against eBay policy to try to sell guns and ammunition.”

A search warrant affidavit filed on Friday stated that investigators wanted to search Cho’s email accounts, including the address Blazers5505@hotmail.com, which Durzy confirmed was Cho’s.

Virginia state police spokeswoman Corinne Geller said investigators are “aware of the eBay activity that mirrors” the Hotmail account. Attempts to reach the Idaho dealer were unsuccessful.