Fraser Health appears to have cracked the mystery behind a recent outbreak of legionnaires' disease in Surrey.
And it appears to be linked to one of the region's largest shopping malls.
Today, the Walmart Guildford Supercentre closed after seven cases of the bacterial illness have been linked to the adjoining mall's cooling towers.
The rest of the 1.2-million square-foot shopping centre remains open.
The mall is owned by Ivanhoé Cambridge. The corporation also owns Metropolis at Metrotown and Tsawwassen Mills within the Fraser Health Authority.
Earlier this month, Fraser Health reported a "cluster of cases" of legionnaires' disease in the Guildford area.
The bacteria can proliferate in a building's plumbing system.
Legionnaires' disease causes a severe form of pneumonia in some people. It's particularly dangerous for those with compromised immune systems, pregnant women, the elderly, children, and those with chronic lung conditions.