Virginia Tech police continued to work Thursday with state and federal law enforcement officials to investigate harassing Internet and e-mail messages thought to have been originated in Italy.

Related postings at YouTube.com have continued to surface since October, despite efforts to shut down accounts used by the suspect, Tech Police Chief Wendell Flinchum said.

The messages, which have included e-mails sent to four students, have referred to the April 16, 2007, shootings and shooter Seung-Hui Cho.

Tech police are working with Virginia State Police, the Federal Bureau of Investigation and Italian police to track down the suspect, Flinchum said.

In a message sent to the campus community this week, police said they do not believe the messages constitute a threat to the university populace.

In October, YouTube closed the account of someone using the screen name "NextKillerVirgTech," who posted racist and skinhead videos, allusions to the April 16 shootings, photos of shooter Seung-Hui Cho and threats to kill law enforcement officials.

Links to blogs and news coverage of the threats were also posted to the page along with mocking and offensive comments.

Four students who in October spoke to reporters for television news reports about the postings were recently targeted through their e-mail accounts, Flinchum said.

The e-mails were sent from either a fraudulent AOL account or from a fictitious vt.edu account referencing Cho.