All three challengers vying to unseat Mayor Thomas Menino will appear together outside City Hall Monday morning to decry the routine deletion of city employee emails.

City Councillors At-Large Michael Flaherty and Sam Yoon, along with South End contractor Kevin McCrea, are planning a 10:15 a.m. press conference to call for an investigation into the issue, which involves top Menino aide Michael Kineavy.

The deletion of the emails may violate the state's open records law.

Menino aides chalk the deletion to an oversight in the computer system which has been repaired, and say opponents are playing politics.

In their capacities as elected officials, Flaherty and Yoon will be sending a letter to the state attorney general, secretary of state and the Suffolk County district attorney.

Flaherty and Yoon will also ask for a City Council hearing to look into the matter.