Police searched for a man who fled from a house in Chiswell Green yesterday evening, after a man in his 60s was assaulted.
A number of areas in Chiswell Green were searched by officers and a helicopter after police received reports of an assault at around 8pm.
A man, suspected of the assault, left the scene and there were then serious concerns for his welfare.
The East of England Ambulance also attended the scene, where a man in his 60s received bruising to his face.
A 37-year-old man from St Albans was arrested on suspicion of assault and is currently in police custody.