The forces helicopter was called out and hovered up above as the man was arrested in Burley Road Oakham around 6.15pm
The police called Oakham Town Council to open the public loo's in Church Street, Oakham to search for a discard knife. The Town Clerk said he was able to lock up the loo's at return home at around midnight.
A knife was found by police in a Royal Mail Post Box and the knife may have been used to stab another person.
Police are describing the matter as a domestic incident.