LOS ANGELES — The mayor of San Marino, Calif., resigned Tuesday after being caught on video tossing a small bag of dog poop into a neighbor’s yard.

Dennis Kneier announced his resignation in a letter addressed to fellow City Council members, saying that the June 7 incident was “a lapse in judgment.”

Kneier’s neighbor Philip Lao discovered the small bag outside his home. He reviewed video from his home’s surveillance cameras, which showed Kneier tossing the bag. Lao believed the mayor intentionally tossed the bag in retribution for putting a “No Poop Zone” sign outside his home and publicly opposing a proposed dog park.