San Francisco's FiberWAN network, which fell into the hands of a rogue administrator who changed user passwords, is now back under government control.

Court records filed by the city in its ongoing case against network administrator Terry Childs state that it has spent around $200,000 working on the network but that the final bill may rise to $1m.

"We are working with our consultants to make sure we have checks and balances in place to make sure this doesn't happen again," Ron Vinson, a spokesman for the Department of Telecommunications and Information Services, told CBS.

Vinson added that there are still some "unidentified items of equipment" on the network, but that "we don't feel at this time that our system is vulnerable as a result".

Childs is still being held in prison after failing to raise $5m bail. The standard bail for murder suspects is usually $1m or $2m.

The man is accused of locking out administrators from the FiberWAN network, which carries over 60 per cent of the city's network traffic, after he was suspended by administration officials.

Childs eventually handed over the passwords that would allow access after a secret meeting with city major Gavin Newsome in his prison cell.