LIHU'E, Kaua'i — An assistant chief of police has filed a whistleblower complaint against the county and the police department, alleging that Kaua'i Police Chief K.C. Lum retaliated against him for raising issues of possible violations of state and federal laws.

The lawsuit by Assistant Chief Clayton Arinaga is the latest chapter in the police department's troubles. This week, the police union and Mayor Bryan Baptiste urged the police commission to remove Lum as chief. Before that, the County Council announced it will conduct an investigation of the police department. And police commission members themselves said they are prepared to oversee an inquiry of the department called an upward appraisal.

The State of Hawai'i Organization of Police Officers complained that morale is low and that Kaua'i police officers are leaving the department at much higher rates than officers in other counties. The department faces numerous union grievances, complaints of police brutality and complaints by officers against other officers. Baptiste said Lum has been unable to unify the fractured department he inherited, and that problems have worsened during his tenure.

Lum was off-island and not available for comment. County Attorney Lani Nakazawa and Prosecuting Attorney Craig De Costa could not be reached for comment.

Honolulu attorneys Margery Bronster and John Hoshibata, who represent Arinaga, say in the complaint that Arinaga repeatedly urged Lum and Deputy Chief Ron Venneman to investigate a case in which three vice squad officers used government funds to fly to Maui for a conference, then never attended the conference. Arinaga's complaint said Lum and Venneman never investigated and ordered him not to initiate his own investigation.

The complaint says Arinaga was then punished by being placed on paid leave for a month in November and December 2005, and later ordered to take vacation time for days when he was on administrative leave. Meanwhile, the prosecuting attorney's office launched an investigation of Arinaga for hindering prosecution, involving events that took place in 2000. The details of the case have not been released, but the lawsuit says it involves a situation in which Arinaga intervened in a threatened suicide and "defused the situation so that no one was harmed or injured."

Arinaga is back on the job, but Hoshibata, in a letter to Nakazawa, said the investigation is apparently continuing.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.