SAN FRANCISCO (CBS SF) — San Francisco police have arrested a man suspected of posting a racist threat on Twitter against the acting police chief.

The tweet, which was posted Saturday, included a photo of Acting Police Chief Toney Chaplin beside an image of a guillotine and the caption “Let us behead this black man, please!”

The post also included a sign that read, “White Trade Only.”

The tweet came from a Twitter account belonging to “LambofGod” (@BethesdaSavior), and the account features a link to a blog that focuses on white supremacy with posts of swastikas and lynchings.

The day the tweet was posted, San Francisco Police Department’s Special Investigation Division began a probe of the alleged criminal threats against the acting chief, according to a statement from San Francisco Police Department spokesman Officer Carlos Manfredi.

Monday, a warrant was served at a home on the 2600 block of Ortega Street and police arrested a suspect, identified as 60-year-old Donald Eric Hoganson, Manfredi said.

Hoganson was in custody but had not yet formally been booked. Manfredi said the investigation was still ongoing.