BOSTON -- No criminal charges will be filed in the case of a city of Boston employee who deleted e-mails on his work computer, Attorney General Martha Coakley's office announced Thursday.

The investigation sought to determine whether Michael J. Kineavy, chief of policy and planning for Boston, had committed a crime through his practice of routinely deleting emails and emptying various Microsoft Outlook E-mail folders on his work computer.

The investigation included a review of thousands of pages of documents from the city, a forensic analysis of Kineavy's computer systems and the interviews of more than a dozen witnesses.

During the time that Kineavy routinely deleted his e-mails, the City of Boston’s Employee Handbook indicated to employees that all e-mail was automatically retained by the city's computer systems.

Further, the City of Boston Archives and Records Management Division E-mail Management and Retention Policies specifically encouraged city employees to delete e-mails on a daily basis. Interviews with several city employees revealed a misunderstanding among many employees about how the city’s e-mail system worked and how e-mails were maintained on that system, Coakley said. Based on these and other factors, no criminal charges are warranted against Kineavy because there was no evidence that Kineavy was knowingly "destroying" his e-mails.

"Our investigation revealed that during the time Mr. Kineavy was accused of improperly deleting e-mails, the city's own policies indicated that all e-mails were being saved on a back-up server and specifically encouraged employees to delete e-mails on a daily basis. It also revealed a shared misunderstanding by many City Hall employees that e-mails were being backed up on the city's server. Based on these and other factors, the facts did not demonstrate that Mr. Kineavy was knowingly destroying his e-mails and do not support criminal charges against him," Coakley said.

Since the initial public records request, there have been a number of steps taken to remedy the problems that were uncovered, Coakley said. The city has purchased and installed equipment that permanently captures and stores all e-mail sent or received by City Hall employees.

It also had updated its e-mail policies and begun implementing a more comprehensive public record training schedule.