A 40-year-old woman died on Sunday in Yarl's Wood immigration removal centre in Bedfordshire, the Home Office has confirmed. Police are investigating the woman's death and the prisons and probation ombudsman has been informed.

There are unconfirmed reports that the woman was heard shouting for help shortly before she died. She was understood to be from Jamaica. A spokesman for the East of England ambulance service said: "We were called to Yarl's Wood immigration removal centre at 8.17am after receiving reports that a woman was in cardiac arrest. We attended along with the air ambulance service. She was sadly pronounced dead at the scene."

There have been 12 deaths in immigration removal centres in recent years. Campaigners have been calling for the closure of Yarl's Wood. Richard Fuller, a Conservative MP whose constituency is close to the facility, has repeatedly condemned the detention of women there.

Emma Mlotshwa, co-ordinator of the charity Medical Justice, which works to protect the health of immigration detainees, said: "We are shocked but not surprised to hear of this tragic death. Any death in immigration detention is avoidable as immigration detention is optional.

"Our volunteer independent doctors have seen an alarming number of incidents of medical mistreatment. The only thing we are surprised about is that there have not been more deaths."

"Indefinite immigration detention has a toxic effect on health - we have seen detainees' conditions deteriorate and some have become mentally ill during their incarceration."

A Home Office spokesperson said: "Sadly, we can confirm the death of a female detainee at Yarl's Wood on 30 March. It would not be appropriate to comment further as the death is subject to a police investigation. The prisons and probation ombudsman has been informed in line with standard procedure."

In July, 2011, Muhammad Shukat died at Colnbrook immigration removal centre near Heathrow. An inquest found that in his case staff failed to act quickly enough to save his life. The Home Office described the inquest verdict into his death as "deeply worrying".