An underwater search has been taking place in the River Freshney in Grimsby.
Two police vans are at the scene on Haven Terrace from the Regional Marine and Underwater Search Unit.
The unit uses specialist divers for searching areas of water and covers the whole of Yorkshire and Humberside.
A Humberside Police spokesperson said: “Police have been in attendance today at the River Freshney undertaking searches as part of an ongoing investigation.
“For operational reasons we are not providing further information at present.”