London ? British authorities on Friday disclosed four new London locations, including a Moroccan restaurant and a lap-dancing club, at which investigators have found the kind of radiation that killed former Russian intelligence agent Alexander Litvinenko in November.

The investigation stretched over 47 locations, the Westminster City Council said. The newly disclosed sites were Hey Jo, a lap-dancing club in central London; Litvinenko’s personal Mercedes; Dar Marrakesh, the restaurant; and a gray taxi Mercedes.

Litvinenko, an exile and harsh critic of Russian President Vladimir Putin, died at age 43, three weeks after polonium-210 was apparently slipped into his tea in the bar of a London hotel.

Investigators have been aided by a series of positive readings for polonium-210 radiation, marking a trail along which the killer or killers and victim moved. Of the 47 locations examined, including eight aircraft, radiation was found at 27 sites, the Westminster council said.