A construction block was thrown through the window of Bonnie and Jason Devine's southeast home and a swastika was spray-painted on the front door. (CBC)

Calgary police are investigating an alleged hate crime in the city's southeast early Saturday morning.

Bonnie Devine, who is involved in an anti-racism group, told CBC News a construction block was thrown through her front window and a swastika was spray-painted on her front door.

"We woke up to the sound of glass breaking, and when we came downstairs we discovered that a cement block had been thrown through the glass window, and then our children had yelled that there was glass in their room as well," she said.

Devine, a spokesperson for the advocacy group Anti-Racist Action Calgary, believes her family was targeted because of a rally the group is holding in the Bridgeland neighbourhood of Calgary on Oct. 10.

She said similar violence has happened in the past and her home was firebombed last year.

"When this happens, it actually fuels us to keep advocating for it," Devine said.

"It keeps pushing us further because the organization is such a grassroots project … when there's activity ... that's when we're organized and that's when we call for all anti-racist activists to come out and speak out."

Police are investigating and looking for suspects.