New York, Aug 6 (IANS) A 42-year-old Indian American businessman in New Jersey, whose family was the target of what was apparently a hate crime is shocked to find that its perpetrator was none other than his teenaged son.

Police in Wayne, New Jersey, who along with Prosecutor's Office, New Jersey's State Division of Criminal Justice and the Federal Bureau of Investigation (FBI), launched an investigation into the crime, traced it to the son through his computer at home, reports said.

In May, the family discovered graffiti spray-painted at the back of their two-storey house, front steps and rear patio with threats and profanities along with references to their Hindu faith and their Asian Indian decent.

The black, orange and neon green graffiti painted threats like 'We Kill U', 'We will fire your house', 'Watch Your Kids' and 'I HATE INDIANS' among others.

Prior to that, in January, they received a series of hate mails and found threats painted on their garage doors. The family had moved to their new home in the Toms Lake community in Wayne in November last year.

According to a report in India Post, an ethnic newspaper, a police patrol car was stationed at the house and surveillance cameras were set up in addition to conducting dozens of interviews with suspects.

The son, the report quoted police sources as saying, had lately been leaving threatening messages in a cardboard box on the premises of the house and had also escalated the volley of e-mail threats.

Detectives from the Prosecutor's Office then traced the e-mail threats to the son's computer after seizing it. Though he had tried to delete the e-mail files, the detectives were able to scan the computer for a full history.

Detective Captain Paul Ireland of Wayne Police told India Post that the boy had been released to be in the custody of his father while further investigations into finding his accomplices continued.

"They all appear to be juveniles but that (premise) might change as investigations continue. We are still interviewing a lot of his friends and acquaintances," the detective said.

The Indian American businessman, who was born and brought up in Tanzania and moved to Passaic in the US when he was 17, had at the time of the crime said on condition of anonymity that his three children - two boys, aged 16 and 11, and a daughter, 13 - were aware of the graffiti but he would not let them see it.

Wayne in Passaic County is a small township of around 54,000 people. It is a cosmopolitan community with a mix of African Americans, Hispanics, Pacific Islanders, Asians and Native Americans besides Whites. Indian Americans comprise around two percent of the population.