California’s political watchdog agency filed a lawsuit on Thursday seeking to force a Los Angeles law firm to identify who paid signature gatherers trying to force a public vote on Sacramento’s arena subsidy.

The Fair Political Practices Commission’s suit against Loeb & Loeb charged that the high-powered firm has “failed and refused” to report the source of the money, despite warnings that it had violated the Political Reform Act by failing to meet a state financial disclosure deadline.

Loeb & Loeb represented the Maloofs when the family reached a deal in January to sell the Sacramento Kings to a group in Seattle. The Maloofs have denied any involvement in the signature campaign, and members of the family were not available for comment Thursday.

Reported by Ryan Lillis, Dale Kasler and Tony Bizjak of theĀ Sacramento Bee