Recovering evidence from a tar pit is challenging because tar is very viscous and sticky, which hinders the functionality of remote operated search equipment designed for water. Almost zero visibility and the entrapment nature of tar also make it difficult to navigate and retrieve objects. Discussions about using drone technology are focused on monitoring and protecting the site.
Recovering evidence from a tar pit presents unique challenges, primarily due to the physical properties of the tar itself. The La Brea Tar Pits, for example, are well-known for trapping and preserving biological specimens, particularly fossils, as described in the Science Friday video featuring Dr. John Harris. This preservation is due to the thick, viscous nature of tar, which engulfs and secures material over time.
In the context of a 2011 murder case, the inability to use remote operated underwater search equipment in a tar pit for evidence recovery is likely because the equipment is not designed to function in such a dense, sticky medium. Standard underwater search equipment works best in water, which poses much less resistance than tar. Moreover, tar can easily damage sensitive equipment.
Another factor preventing effective use of such equipment could be related to visibility and maneuverability. In a tar pit, visibility is near zero, making it incredibly hard for any remote operated equipment to navigate or identify objects. Tar pits, like the La Brea Tar Pits mentioned, are notorious for their ability to entrap and hold things in place, negating the retrieval ability of remote operated devices.
Current discussions about monitoring the area, such as those involving drone technology as suggested by Isla, focus on surveillance rather than retrieval. This technology is more about preventing human interference that could disrupt the site or introduce contamination.