Democratic congressional candidate Brent Welder — who is seeking to challenge incumbent Republican Kevin Yoder — sent out a campaign email Saturday that linked the deaths of two deputies in Kansas City to the gun control debate, according to the Kansas City Star.

The email provided a link to an online petition to tell Yoder to stop accepting money from the National Rifle Association, as well as a link to a campaign fundraising page for Welder. The email even included promotional information about an upcoming gun control rally.

On Monday, Welder apologized for the email.

Investigators believe that Deputies Patrick Rohrer and Theresa King were shot and killed by a subject who had somehow obtained one of the deputy’s guns.