A Colorado sheriff's deputy shot while on duty has died after he was taken off life support.

Mesa County Sheriff Matt Lewis announced the death of Deputy Derek Geer late Wednesday night.

The sheriff's office says Geer was shot by a 17-year-old boy who was seen walking around with a gun Monday in Grand Junction.

The Daily Sentinel reports that Geer was shot within a minute of telling dispatchers he was approaching the teen, according to police radio traffic.

Geer wasn't expected to recover but was kept on life support so that his organs could be donated. The 15-year department veteran was married and had two children.

His funeral will be held Monday in Grand Junction. Prosecutors plan to charge the teen as an adult.