ALBUQUERQUE, N.M. (AP) — A fifth Albuquerque police officer has resigned during an investigation into alleged wrongdoing by officers assigned to a unit charged with stopping impaired drivers, according to authorities.

City Police Chief Harold Medina said Joshua Montaño submitted his resignation Wednesday after he failed to appear for multiple interviews with internal affairs, Albuquerque TV station KRQE reported Thursday.

The four officers who previously resigned have been identified as Justin Hunt, Honorio Alba, Harvey Johnson and Nelson Ortiz.

Authorities have said the investigation into the DWI unit centers on accusations that officers were taking bribes to get driving while intoxicated cases dropped.

Nobody has been charged, and authorities said the investigation is ongoing with the FBI also investigating.

The police department launched the probe into officers who were currently or previously working for the DWI unit.

According to documents obtained by the Albuquerque Journal, the federal probe began after a stop by an officer in August in which he allegedly told the driver to contact a specific attorney to ensure that a case would not be filed.

More than 150 cases alleging that motorists drove while intoxicated have been dismissed as part of the probe.

Three Albuquerque police officers combined filed 136 of the 152 DWI cases, and at least 107 of those were filed last year. That was 10% of such cases for the department that year, according to authorities.