New London police said Monday that due to a mechanical failure of the department's voice recording archive system they have lost about a week's worth of recorded 911 calls, including those made after the June 21 murder of 23-year-old Vernell Marshall outside of Ernie's Café on Bank Street.

The police department learned that calls made between June 14 and 21 were missing after a local defense attorney asked for emergency calls stemming from his client's breach of peace charge, and the calls could not be found.

Steven Kurcinik, acting computer systems supervisor for the city, would not comment further on the report and said he was not authorized to speak on the matter. The city manager's office referred all comments regarding the lost calls to the police department. Reached by cell phone, Chief Bruce Rinehart, who was out of the office Tuesday, said he did not know how many calls had been lost or have more information about the nature of the mechanical failure. Capt. Michael Lacey did not return calls Tuesday.

Local attorneys said that 911 calls are frequently used as testimony in criminal trials, particularly in cases in which an eyewitness phones during an incident and describes a suspect or in which a witness cannot be found or recants a statement made to police.

Business Electronics Inc. in Cheshire, which counts 60 to 70 percent of Connecticut's emergency services departments as its clients, explained Tuesday that while software differs from department to department, most modern systems have redundancy built into the technology that logs 911 calls and other voice recordings as audio files.

Rich Bartoli, vice president and general manager at BEI, said software can be packaged to simultaneously record 911 calls to a hard drive and to one or more DVDs. When the DVDs are full, he said, most departments have an alarm that will sound to let them know that the disks need to be changed. If the disks aren't changed, he said, the system can automatically erase the oldest calls on the hard drive.

There are also options for redundant power sources, in case the power goes out at an emergency services center, Bartoli said.

Some departments opt to use their own in-house network to archive 911 calls, in which case, Bartoli said, they are dependent on the network working to ensure that the calls are properly archived.

“The thing with New London is — it's not uncommon. You're dealing with machinery. You're dealing with electronics. Sometimes these things fail,” said Lt. William T. Molis Jr., in charge of the records division at Norwich Police Department.

Norwich police use an alarm system and battery backup in case the power fails, Molis said, and retain all 911 recordings for 30 days — as required by law — unless they are requested by an attorney, member of the public or the department. After that, the calls are permanently erased.

It is possible not to hear the alarm, Molis said, and while the department is confident in its system's redundancy, glitches could occur. Even before computerized recordings, Molis said, 911 tapes could break or become demagnetized.

“I'd be willing to say that the possibility of it happening would not be uncommon in any department,” Molis said.

New London attorney Gregg W. Wagman said whether the missing tapes prove crucial to a future criminal trial regarding the June 21 murder depends largely on what information is contained in the tapes.

“Certainly in many cases it's a nonissue,” he said.

New London attorney Matthew Berger said depending on what is or is not on a 911 tape could significantly change the outcome of a trial.

“Missing evidence can be a case for the state to drop charges or for an acquittal,” Berger said. “... The question is what exactly is on the tape.”