LOS ANGELES (KABC) -- The union for Los Angeles Police Department officers has filed a federal lawsuit against the city, the department and Chief Charlie Beck over the department's officer-discipline process.The Los Angeles Police Protective League said the suit is meant to put stop Beck's "corrupting influence" over the LAPD Board of Rights, a three-person panel charged with deciding discipline cases for officers facing long-term suspension or termination.The union argues that because two of the three officers on the board are police captains, who depend on the chief for their promotion, the board is predisposed to vote Beck's way regardless of merits. They said in some cases, that has resulted in decisions against officers based more on politics than policy."Their promotion opportunities depend upon the chief," said LAPPL attorney Greg Adam. "The chief of police basically controls those captains."The union wants a federal court to declare that the board's composition violates the "due process" clause of the U.S. Constitution's 14th Amendment.Mayor Eric Garcetti said he has been looking at the possibility of adding one or two additional civilians to the board."I've been working very closely with the union and with our police chief to see if we could pilot something that would add an additional civilian or two to folks who are essentially the jury whenever there are disciplinary hearings," Garcetti said. "But it may require going to the ballot."According to the Los Angeles City Attorney's Office, the composition of the board was determined by voters in a ballot measure, so changes would need a similar process. The office said such a change could be presented to voters as early as this November.The LAPD declined comment on the lawsuit.