The 39-year-old, whose name and occupation are suppressed, is on trial before the Dunedin District Court charged with criminal harassment, threatening to do grievous bodily harm and intentional damage.
The complainant - a Dunedin business owner - and his sister, a professional, also have name suppression until at least the end of the trial.
The man gave evidence about his ordeal yesterday.
"I was scared. I was actually really scared for quite some time. I wouldn't work till dark, I wouldn't be last to leave work. I wouldn't even go outside at night-time at home ... because I thought someone was coming to get me,'' he said.
"It was a living hell, to be honest.''
Crown prosecutor Mitchell McClenaghan said the alleged feud began with a seemingly innocuous incident on June 14, 2012.
The complainant arrived at work to find a car blocking the rear entrance to his work premises.
He tried to contact the owner by calling a phone number on the window but, unable to speak to the defendant, he called the Dunedin City Council and the car was ticketed.
A few hours later, when the driver returned and found the infringement notice, he confronted the business owner, who admitted calling in parking wardens.
The defendant vowed he would get off the $40 ticket, the court heard.
"I was a bit intimidated because he did it right in front of my face,'' he said.
The next day, the car was parked in the same spot, prompting the businessman to text: "clever parking, dick head''.
He then posted on Facebook a picture of the inside of the car which showed a child seat secured by motorcycle cables, with a disparaging comment.
Mr McClenaghan said what followed was a varied campaign of harassment.
A couple of months after the original flashpoint, the man said he started receiving photos of a partially-clothed woman from an unknown number.
By early 2013, the complainant began getting numerous text messages and calls from gay men.
After speaking to one of them, he discovered his contact details had been left at a notorious homosexual meeting place on the coast.
"I found my phone number was plastered all around it written in pen saying I was gay and looking for a good time, that I could be there in five minutes, and I had all sorts of men texting me from there,'' he said.
"I was pretty upset. I was standing up there crying because my name was everywhere.''
In 2014, it is alleged the state employee also set up a profile on a dating website featuring the other man's photo and name.
The advertisement had the title "new gay male to play'' and the person running the account encouraged people to contact the man.
The Crown said there were instances of the complainant's name being "graffitied'' around town along with homosexual references.
His business was targeted as well, Mr McClenaghan said.
Twice it was hit with a "paint-ball grenade'', the man told the court, and adjoining business owners were told in an anonymous letter their neighbour was a sex offender under investigation by police.
In September 2014, the man said he was pushed to breaking point and used a new phone to "trap'' the offender.
He sent messages complimenting his appearance and offered to hook up at the Roslyn toilets.
Under cross-examination from defence counsel Anne Stevens, he accepted it had not flushed out the defendant and he had no evidence her client was behind the campaign against him.
The Crown said the most "alarming and malicious'' threats came on December 2, 2014, when the defendant allegedly told the man to "buy something bullet proof'' and to "get your affairs in order''.
Mr McClenaghan accepted the prosecution case was circumstantial but said a search warrant executed at the home of the accused was telling.
"Analysis of the electronic devices found at his address showed he had an unhealthy and warped interest in the complainant,'' he said.
There was also a cellphone exchange between the defendant and a friend poking fun at photos of the man, which Mr McClenaghan said was consistent with the other abuse dealt out over the 30 months.
The trial, before Judge Paul Kellar, is expected to last a week.
