BERMAN: Breaking news. British counterterror police are now investigating an incident that has left two people in critical condition after being exposed to an unknown substance. This happening just miles from where a Russian double agent and his daughter were poisoned back in March. Our Erin McLaughlin live in Amesbury in England with the breaking details. Erin, what are you learning?</s>ERIN MCLAUGHLIN, CNN INTERNATIONAL CORRESPONDENT: Hi, John. Well, this is yet another mystery that authorities here in Wiltshire are working furiously to solve, being very tight-lipped at this point with the details. But what we do know is that on Saturday evening, a couple yet to be identified by officials, in their mid-40s were found at the apartment block behind me unconscious. Now initially, authorities suspected a drug overdose -- cocaine or heroin. Now, they're saying they don't know for sure and they've declared a mass incident and have cordoned off the apartment block. Also, a local pharmacy, as well as a Baptist church where residents tell us the couple had attended a fun fair just hours before being found unconscious. This has this area on edge raising a lot of eyebrows and concerns because of its proximity, of course, to Salisbury which is just six miles away. Four months ago, that is where the ex-Russian double agent Sergei Skripal and his daughter Yulia were found unconscious, poisoned by a weapons-grade nerve agent. The British government has since blamed Russia for that attack. Now we have heard from the police commissioner in this area tell the BBC earlier this morning that there -- at the moment, there are no links between what happened to this couple at this point and the Skripals. But this is the subject of this ongoing investigation and counterterrorism police have been brought in as well -- John.</s>BERMAN: All right, Erin McLaughlin for us in Amesbury. We'll stay on this all morning. Really appreciate it. Also, we're following new developments out of Thailand where rescuers are trying to reach and get those 12 kids trapped in the cave out. We have new developments and we'll speak to an expert diver, next.
U.K. Anti-Terror Police Join Inquiry Into Unknown Substance