A woman was left “angry and shocked” after seeing a masked man looking into her kitchen window from behind the home.

Herts Police have asked residents to “report similar incidents” after the “suspicious activity” in Gade Avenue at around 2pm on Friday (August 11).

The woman, who reported the man in a medical mask to police, believes he may have been looking for empty properties during the holidays.

When he saw she was in he waved at her, despite standing in the side alley by her home that he apparently could only have accessed by hopping a fence.

“He wasn’t supposed to be there, I was angry and shocked," she said.

“I went outside to say 'what the hell are you doing' but he had vanished.”

Herts Police issued a description that said: “The man was described as in his twenties, around six-feet-tall with short, black hair, and of a lean build.

Watford Observer: A garden fence at the property, which the residents think the man may have climbed over.A garden fence at the property, which the residents think the man may have climbed over. (Image: Contribution)

“He was wearing a medical mask. The local policing team have been made aware and residents should report any similar incidents.”

After reporting what happened to police, the residents warned their neighbours.

“We’ve never had anything like it,” the woman, in her 50s, added. "It’s not good for all the people living in the area.

"There are lots of elderly or vulnerable people.”