The city of Long Beach has launched an independent review of the police department’s use of an  app that deleted text messages, while American Civil Liberties Union on Friday said the practice is illegal and may have compromised hundreds of criminal and civil cases.

The Long Beach Police Department made international headlines this week when it was revealed that the department for years has used an application called TigerText that allows officers to message each other with potentially sensitive information before it’s automatically deleted.

In response, the department has suspended use of TigerText and says it is reviewing its protocols for communications and retaining records.

The city on Friday said it has hired an outside firm to independently review the use of the messaging application.

“I applaud the Chief’s decision to immediately discontinue use of the messaging application and strongly support the initiation of this independent review to understand how the system was used and to ensure that the City is complying with all applicable laws,” Mayor Robert Garcia said in a statement.

The review will include the origin and implementation of the messaging application, how the app was utilized, record retention and city policies and procedures for documenting evidence.

In a letter to Long Beach’s city attorney on Friday, the ACLU of Southern California said it was “deeply troubled” by the allegations.

“The use of TigerText by the department violates California law requiring the preservation of city records, and may call into question the integrity of many hundreds of civil and criminal cases that rely upon evidence provided by LBPD officers,” the letter said.

While suspending use of TigerText is a “step in the right direction,” the ACLU said, the city must come into full compliance with the law by permanently ending the practice and prohibiting its officers from using self-destructing messaging applications for work. 

The ACLU has requested additional documents relating to the use of TigerText but said the city has so far failed to provide a complete record of invoices and contracts, communications or any policies on the application.

Long Beach City Attorney Charlie Parkin has said that he was unaware of the practice and never would have sanctioned a system that automatically deletes messages.

The results of the city’s independent review will be made available to the public to the extent allowable under California state law, officials said.

Long Beach Police began using the app in 2014 when the department transitioned to iPhones, which did not have a built-in secure communication feature, city officials said.

Officials said the primary purpose was to allow for immediate and secure communications for operational and personnel matters.

Of the 291 Police Department-issued mobile devices, the application is installed on 145 devices, including those for command staff and specialized details such as Homicide and Internal Affairs.

City officials said the first purchase order for the software came in June 2014 for $9,888. The contract has been renewed each year for the past four years. Under city policy, purchases under $25,000 are approved at a department level.

Police Chief Robert Luna in a statement said he agrees with the review and will “cooperate fully.”

The Los Angeles County District Attorney’s Office said it has referred the matter to its Justice System Integrity Division for review.