Federal agents do not need a search warrant to monitor a suspect's computer use and determine the e-mail addresses and Web pages the suspect is contacting, a federal appeals court ruled Friday. In a drug case from San Diego County, the Ninth U.S. Circuit Court of Appeals in San Francisco likened computer surveillance to the pen register" devices that officers use to pinpoint the phone numbers a suspect dials, without listening to the phone calls themselves. In Friday's ruling, the court said computer users should know that they lose privacy protections with e-mail and Web site addresses when they are communicated to the company whose equipment carries the messages. The search is no more intrusive than officers' examination of a list of phone numbers or the outside of a mailed package, neither of which requires a warrant, Judge Raymond Fisher said in the 3-0 ruling. Defense lawyer Michael Crowley disagreed. His client, Dennis Alba, was sentenced to 30 years in prison after being convicted of operating a laboratory in Escondido that manufactured the drug ecstasy. Some of the evidence against Alba came from agents' tracking of his computer use. The court upheld his conviction and sentence. Expert evidence in Alba's case showed that the Web addresses obtained by federal agents included page numbers that allowed the agents to determine what someone read online, Crowley said. The ruling "further erodes our privacy," the attorney said. "The great political marketplace of ideas is the Internet, and the government has unbridled access to it."