(Capcom's primary storyline)
The Secret Security Patrol Team was an Umbrella paramilitary unit. It is mentioned in a Fax to the Manager of Sanitation at the Arklay Laboratory. The entire team sent to the Arklays had apparently been eradicated during their search, perhaps by the infamous Cerberus pack - who killed and ate a number of people living or hiking in the mountains.
The very similar "1st Investigation Unit" may be related to the Patrol team.