A Golders Green woman who sent dog excrement in the post to a former lodger received a harassment conviction and a conviction for assault on a police officer, at City of London Magistrates’ court last week.

Yanina Heuberger, 53, was found guilty of sending an abusive email and a further offending letter to lawyer Lisa Hirsowitz following a small claims settlement over the lodger’s rental deposit.

The email, which Ms Heuberger admitted sending the day after she was ordered to pay her former lodger £700, called Ms Hirsowitz and her boyfriend “thieves and liars”.

It predicted: “People will come to your home and cause you grief and harm”, and told the couple that they “will not have rest or peace to enjoy life”.

A few days later, Ms Hirsowitz and her boyfriend were in synagogue and saw Ms Heuberger. While the couple insisted they were waving, Ms Heuberger told the court: “They were pointing at me, telling their friends who I was. I found it quite distressing.

“Clearly the email hadn’t got them to leave me alone, and I had to send a cheque anyway, so I thought I would send a letter”.

Ms Heuberger, an artist, who describes herself as Orthodox, lives alone with her dog in Woodlands, Golders Green. She wrote Ms Hirsowitz a letter which included the phrase “stinks like s***”. To echo this sentiment, she scooped into the envelope some of her puppy’s excrement, and posted it.

Ms Hirsowitz received the letter, bearing Yanina Heuberger’s return address on the back of the envelope, at her office, law firm Malleson Stephens Jaques, the next day.

“I noticed there was a powdery white residue”, Ms Hirsowitz told the court. “I thought it was poison or some sort of corrosive”.

She threw the letter in her office bin and called security. An entire floor of the city law firm was evacuated while the police Chemical, Biological, Radiological and Nuclear Centre team investigated.

DC Giles Cunningham and two other officers went to Ms Heuberger’s home the next morning to arrest her.

She claimed in court that she had not heard or understood her arrest and caution, a claim directly contradicted by the police officers.

On refusing to remove items from her pockets, an officer moved to handcuff her and a struggle resulted. She was described by Crown Prosecution lawyer Alex Ng as “sitting back [on a desk] and kicking up with full force into DC Cunningham’s groin area”.

This version of events was strongly contested by Ms Heuberger, who alleged that the officers “jumped on her”. She produced as evidence pictures of the multiple bruises she said were sustained during the altercation.

But the bench said it found “the officers credible and their evidence consistent”.

Ms Heuberger, who attends Kinloss Synagogue, was given a conditional discharge, a three-year restraining order preventing her from contacting Lisa Hirsowitz, and was ordered to pay £400 in court costs.