By George P. Hassett

The man alleged to have shot a Somerville police officer tonight was shot and killed during the exchange, according to a release from the district attorney’s office.

The suspect was sought for arrest by Somerville Police and The Federal Bureau of Alcohol, Tobacco, Firearms and Explosives at 6 Gibbens Street tonight when he opened fire on officers, according to a statement from the city.

The man, who is alleged to have shot the officer, was struck by return fire and has now been pronounced dead, according to the DA’s statement.  He is not being identified pending notification of next of kin.  The officer was transported to the Massachusetts General Hospital, where he is being treated.  The police-involved shooting will be investigated by the DA’s office, per protocol.

The circumstances of the shooting incident remain under investigation.  The investigation remains active and ongoing.