Sony sacked security staff just before the April PlayStation Network hack, a new lawsuit claims.
The lawsuit alleges Sony prioritised the protection of its secrets over customer data, Reuters reports.
The lawsuit was brought to a court in San Diego, US, by PSN customers who seek class action status for their complaint.
It claims Sony fired "a substantial percentage" of the Sony Online Entertainment workforce, including many from its network operations, citing a confidential witness.
Apparently Sony suffered smaller breaches in the run up to the April hack, so should have known better.
Sony Computer Entertainment Europe boss Andrew House told Eurogamer at E3 that Sony's data protection was "appropriate" "based on the knowledge we had at the time".
This latest lawsuit follows an April suit against Sony filed almost immediately after the PSN hack came to light.
California-based practice Rothken Law Firm filed a suit on behalf of Alabama resident Kristopher Johns, who complained that Sony didn't take "reasonable care to protect, encrypt, and secure the private and sensitive data of its users".
The PSN breach saw data tied to nearly 100 million Sony accounts compromised. Sony is unsure whether credit card information was stolen.