SAN Francisco authorities are still locked out of the city's official computer network four days after a disgruntled employee removed access for everyone but himself.
Computer engineer Terry Childs, 43, is being held on $US5 million ($5.1 million) bail after refusing to hand over the password to San Francisco's FibreWAN system.
The network handles up to 60 per cent of the city's government data such as emails, employee financial details, police documents and jail records.
Childs was arrested earlier this week after deleting all accounts with access to the system but his own.
The engineer worked in the San Francisco Department of Technology and earned up to $US127,000 a year but had recently been disciplined over poor performance, The San Francisco Chronicle reported.
Childs, who has a previous criminal conviction for aggravated robbery, gave police a false password to the system and later refused to reveal the real one, the paper said.
It is unclear if Childs gave himself sole access to the system with malicious intent.
In the past months Childs had become unusually protective of the FibreWAN system, which he helped to design and build, reports said.
"He was very good at what he did, and sometimes that goes to people's heads... and we think that's what this is about," said San Francisco Mayor Gavin Newsom.
The city has called in engineers from Cisco Systems to regain access to the network, but the process could take several weeks
