The breach took place in February.
Nearly 27,000 patients may have been affected.
The incident made it 'impossible for us to access anything in our scheduling system.'
The FBI and two other agencies issued an alert on Oct. 28.
The attack took place starting on or around Jan. 10.
The practice chose not to deal with the hackers.
They fell victim to malware.
Hackers struck in January.
61K victims may be eligible for compensation.
16,000 California residents have been notified of the incident.
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