LONDON — A second suspect was arrested in the alleged theft of a work by the elusive street artist Banksy of a stop sign adorned with three military drones, London police said Sunday.

A man in his 40s was in custody on suspicion of theft and criminal damage, the Metropolitan police said. A suspect in his 20s who was arrested Saturday was released on bail.

Witnesses who arrived at a street corner Friday in the south London section of Peckham less than an hour after Banksy posted a photo of the work on Instagram said they were stunned to watch a man with bolt cutters remove the sign as another man steadied a bike he stood on.

The incident was captured in photos and video.

Much of Banksy’s political and satirical art is critical of war, and many of his followers interpreted the work as calling for a cease-fire in the Gaza Strip.