The Home Office is under fire about how a “gentle and polite” man lost his life to a killer with a history of violence and mental health problems after officials locked them both up on the same wing in immigration detention.

An inquest which opened on Monday at west London coroner’s court is to explore the role of the Home Office, the Ministry of Justice, health professionals and detention centre subcontractors in the death of Tarek Chowdhury, 64, from Bangladesh, who was killed by Zana Assad Yusif, 33, from Iraq, at Colnbrook immigration removal centre near Heathrow in December 2016.

Tareq Chowdhury.

Yusif, who was well known to mental health services and had 16 previous convictions for 33 different offences, beat Chowdhury to death just two days after the latter arrived in Colnbrook. Chowdhury had lived in the UK for 13 years and was detained by the Home Office as an overstayer when he attended a regular reporting session. Yusif arrived in the UK in the back of a lorry at the age of 17.

Concerns have been raised about the management of detainees in Colnbrook at the time of the killing and the quality of healthcare Chowdhury received immediately after the attack.

Yusif pleaded guilty to manslaughter on the grounds of diminished responsibility because of his mental health problems at a trial at the Old Bailey in London in May 2017. He was sentenced to 15 years in jail.

Forida Habib, Chowdhury’s cousin, said everyone who knew him described him as soft, gentle and polite.

“When we heard he had been detained we never imagined that a couple of days later he would be dead... We hope the truth will be told at the inquest and that lessons are learned from this tragedy.”

The family’s solicitor, Bharine Kalsi, from Deighton Pierce Glynn, said: “This is a shocking case that raises very serious questions about the state of immigration detention system in this country. Mr Chowdhury’s family want answers to questions about the adequacy of the care and management of detainees and of the medical care provided.”

Killings in immigration detention are highly unusual and only one other case has been reported since 2000, that of Olga Blaskevica, 29, from Latvia, who was killed by her husband while both were in Harmondsworth detention centre near Heathrow in May 2003.

There were 11 deaths in detention or immediately after release from detention between December 2016 and December 2017, the highest number ever recorded. More than half involved detainees taking their own lives.

A second death during that period is the subject of another inquest hearing which began on Monday at Lincoln cathedral centre. Carlington Spencer, 38, from Jamaica, died following a stroke at Morton Hall immigration removal centre in Lincolnshire on 3 October 2017. Two friends of Spencer’s, Christopher Richards and Joseph Nembhard, who are key witnesses to circumstances surrounding his death, were due to board a charter flight to Jamaica last month but were granted an 11th-hour reprieve so they could appear at the pre-inquest review hearing.

Richards has now been released from detention. Nembhard is currently detained in Harmondsworth detention centre near Heathrow and was transported on Sunday night by the Home Office to Morton Hall detention centre so that he could appear at the inquest hearing.

Timothy Brennand, the senior coroner for Lincolnshire, said he would issue a summons for Richards and Nembhard to appear in person at the full inquest into Spencer’s death which he has set for 7 October. It is expected to last for two to three weeks.

He said he did not want to “fetter” the Home Office but did want to ensure that “justice was not only done but seen to be done”. The summons for the two men to appear in court in October will represent a significant delay for the Home Office as officials had hoped to deport both men on last month’s charter flight.

It emerged at the inquest that key CCTV evidence from Morton Hall detention centre relating to the circumstances of Spencer’s death may have gone missing. The coroner asked Natasha Barnes, representing the Ministry of Justice, if it was possible that the CCTV footage was “lost, erased or is missing”. She replied “yes”. The coroner has asked for a definitive answer about what has happened to the CCTV footage within 14 days.

In response to the two inquests, a Home Office spokesperson said: “The welfare of all those in our care is of the utmost importance and we expect detainees to be treated with dignity and respect.

“Any death in immigration detention is subject to investigation by the police, the coroner and the independent prisons and probation ombudsman. Any recommendations made following an investigation into a death are treated seriously and action is taken to ensure they are implemented swiftly.”

• In the UK and Ireland, contact Samaritans on 116 123 or email jo@samaritans.org.

• In the US the National Suicide Prevention Lifeline is 1-800-273-8255.

• In Australia the crisis support service Lifeline is 13 11 14.

• Other international suicide helplines can be found at www.befrienders.org