The man was seen by a householder going into the back garden of her home in Kingston Road, Willerby, at 3.30pm on Tuesday.
When she confronted him, he asked if John was there. The man left when she told him no one called John lived at the property.
As previously reported, undercover officers have been patrolling Willerby, Kirk Ella and Anlaby after a spike in burglaries.
In most of the cases, thieves have entered properties through unlocked doors and windows.
On the same day, a male burglar was disturbed when he smashed a window at a house in Well Lane, setting off a burglar alarm.
It happened between 11am and 4pm.
Neighbourhood officer PC Andy White said: "I want to hear from anybody who had similar callers that day or who saw this male."
The suspect is a white man in his early twenties, about 5ft 10in, with short brown hair. He was wearing three-quarter length shorts and a white T-shirt and spoke with a local accent.
Anybody with information should call Kirk Ella police station on 01482 307213.
