A detainee found dead at an immigration centre in London was Jewish, it has been confirmed.

Amir Siman-Tov, thought to be a Moroccan Jew in his 30s, was found dead in the early hours of Wednesday.

He had been detained at the Colnbrook immigration removal centre near Heathrow, in south west London.

It is not known how he died.

Mitie Care and Custody, which managed the centre, sent a note to fellow detainees confirming his death.

It stated: “It is with sad regret that on the morning of 17 February 2016 Mr Amir Siman-Tov passed away.

“The police have attended the centre and we are assisting them with their inquiries. This may be distressing news to some people and I would request that if you would like to speak to a member of staff please do so immediately.”

A friend of Mr Siman-Tov told the Guardian that he had been on suicide watch since his arrival at the centre in recent weeks.

The Home Office confirmed a detainee had died at Colnbrook, but did not comment further.

Mia Hasenson-Gross, director of Jewish human rights group René Cassin, said: “Our thoughts go out to the man’s family and loved ones.

“This tragic incident once again highlights the lethal policy of indefinite detention. This is the 25th death in an immigration detention centre in the UK. The evidence that detention is harmful is indisputable.

“Over 400 migrants, mainly men, are held indefinitely at Colnbrook Detention Centre. The fact that this man is Jewish connects to our community, but this is a policy that affects over 30,000 migrants who are held indefinitely every year in the UK.”

Last year, René Cassin took at group of rabbis to tour a detention centre next to Colnbrook.