Police investigating the deaths of two divers on a wreck off Cornwall are investigating whether silt dumped in the area affected conditions.
The Scylla was sunk in 2004 to create an artificial reef
David White, 42, and Kay Moss, 43, from Gloucestershire, died at the HMS Scylla wreck in Whitsand Bay in August.
Investigations are under way to find out if material dredged from the River Tamar and dumped at Whitsand explains large silt deposits at the site.
HMS Scylla was scuttled in 2004 to create an artificial diving reef.
The Ministry of Defence dredges vast amounts of material from the River Tamar around its base at Devonport to ensure the river is navigable for naval, commercial and leisure traffic.
Experienced diver, Det Con Derek Farrow, who is leading the investigation, said: "It is certainly the case that the Scylla has got a lot of silt on it in the short space of time that it has been down.
"It's a line of inquiry that we are looking at."
Environmental campaigners have argued that waste from the site two miles off Rame Head is not dispersing out to sea, as intended, but polluting inshore waters.
The Royal Navy says that dumping must only happen on the ebb tide (outgoing tide) to limit any deposits inshore on the beach and in shallow waters.
The National Marine Aquarium, which was involved in the Scylla's sinking, said it was still safe for trained divers.