Image caption Stories of rape have emerged at Tutwiler prison in Alabama (pic: Robin Nelson)

New measures are being implemented in the US to tackle rape and sexual assault in prison. But in Alabama, one women's prison has gained a notorious reputation for being unsafe.

Tutwiler prison stands next to US Highway 231, in the town of Wetumpka. Behind the barbed wire is a series of stone-coloured single-storey buildings.

This is Alabama's maximum security facility for women - a place where stories of rape and sexual assault are legion.

On a Sunday morning, Robert Chancey joins a queue of relatives waiting to visit the inmates. He has come to see Monica Washington, his cousin. Toddling along beside Robert, is Monica's little girl - growing tall and strong while her mother serves 20 years for robbery.

The guard told her when he took her in the room what he wanted to do to her Robert Chancey, Cousin of Monica Washington

Away from the prison, Robert explains how Monica got pregnant. "She was raped in prison. She had the baby by one of the guards."

Robert learned about the attack during a prison visit when Monica was already two months pregnant.

"The guard told her when he took her in the room what he wanted to do to her and she said 'No'. He told her: 'Who do you think they're going to believe - you or me?' So she proceeded just to do what he wanted her to do."

Robert says his cousin was too frightened to report the rape, but prison gossip meant she could not hide the pregnancy - or how it happened - for long.

A Montgomery-based NGO, Equal Justice Initiative (EJI), investigated events at Tutwiler. Charlotte Morrison - an EJI lawyer representing Washington - says there are other cases involving the prison's staff.

"We know of numerous pregnancies, including three since 2009. We interviewed over 50 women at Tutwiler - what we found was really disturbing.

"Every single woman we interviewed had been either sexually assaulted, sexually harassed or had witnessed another female inmate being sexually harassed or sexually assaulted."

But this is not about one institution in one southern state. The United States is the most incarcerated nation on earth - more than two million inmates are behind bars in federal and state prisons, and local jails.

A recent survey by the Federal Bureau of Justice Statistics estimated 9.6% of former inmates at state prisons across the US reported one or more incidents of sexual victimisation during their most recent period of incarceration. About 5.4% of former state prisoners reported an incident involving another inmate, and 5.3% reported an incident involving staff.

'I was raped by a prison nurse' "The guards say they can count you wherever you are," says Felecia Dixon, recently released from prison in Alabama after serving a sentence for theft and drug offences. "On the commode, naked in the shower, getting dressed or whatever - they just walk in. If they were attracted to you, when you get in the shower, they come in to see you." Felecia worked as a cleaner in Tutwiler prison's medical centre, and got to know a male nurse who assaulted her. "Afterwards I was devastated because I didn't know what to do. I mean, I'm a convicted felon, doing my time, paying back my debt to society, and then I'm raped in prison." The Alabama Department of Corrections investigated the incident and the nurse lost his job - but he was never convicted. With the assistance of EJI, Felecia reached a financial settlement with the nurse.

The US Congress has taken action, and the Prison Rape Elimination Act (PREA) came into force last August. It sets out how prisons and jails should investigate and respond to complaints, how inmates should be able to report abuse, and recommends prisoners be guarded by same-sex staff where possible.

The Alabama Department of Corrections says it is working towards compliance with the PREA standards, but would not allow the BBC to visit any of its facilities.

At Florida's Turner Guilford Knight correctional facility, one of five jails run by the Miami-Dade Corrections and Rehabilitation Department, many of the PREA recommendations are being implemented. Staff are trained by Just Detention International (JDI) - an American NGO which has campaigned on prison rape for decades.

On arrival at a Miami-Dade jail, prisoners are advised on how they can keep safe and they have access to a 24-hour hotline. Calls go through to a local rape treatment centre and to Mujer, an NGO where the phone is answered by Ana Obregon.

"In October I had about 18 calls," she says. "The majority are from individuals or by friends of individuals who are identifying as gay - all of them have been men. There's a lot of unwanted touching going on. I have had two who have reported rape."

Campaigners believe that being able to report an assault to an outside organisation - like Mujer - is critical. But the prison context is complex, and the reporting system is open to abuse.

"Since the beginning of this year we have yet to experience an alleged assault we've been able to substantiate," says Marydell Guevara, assistant director of Miami-Dade Corrections and Rehabilitation Department.

"Prisoners may gamble with chips and candy bars. Let's say I was on the losing end, and I owe you five candy bars. Well, I'm going to get on the rape hotline and say: 'My cellmate Jo has sexually assaulted me.'

"They know what our protocol is - we come in, do a full investigation and in the interim, we separate them. So sometimes prisoners use it as a tactic to get someone moved out of their cell."

But this does not invalidate the system, she says. "I'd rather have 100 false reports than have one real one that we miss."

Image caption New federal guidelines have been issued in Miami-Dade, Florida

The new PREA standards are already legally binding for America's federal prisons - state facilities have another year to comply. But for local jails - like Calhoun County, back in Alabama - the situation is less clear-cut.

Larry Amerson believes local sheriffs like him already look out for inmates' safety, and he does not believe the statistics.

"I think they are greatly over-stated," he says. "Do sexual assaults happen? Yes. Are some inmates in particular at risk? Yes. But in 37 years doing this job, I'd be surprised if it was 2% - unwilling participation.

"There is willing participation in sexual acts every day [in jails]. The question is - when does it cross that line?"

That may sometimes be hard to unravel in cases involving only inmates. But those implicating members of staff, especially when a baby has been born, are less ambiguous - aren't they?

In Monica Washington's case, there was a prosecution - but not for rape. The charge against the officer was "criminal sexual misconduct".

Her cousin Robert Chancey still cannot quite believe it. "He got six months. I don't even understand that. That's like a slap on the wrist!"

So why wasn't the officer charged with rape?

"Because there was no investigation done in the case," believes Monica Washington's lawyer, Charlotte Morrison.

"Ms Washington was never interviewed or questioned by the district attorney's office or the police - she was only questioned by the Alabama Department of Corrections."

I'm still getting looks from certain officers like 'I can't believe you did that', or whatever. I have to be on my P's and Q's always dealing with officers and inmates Monica Washington, Prison rape victim

The man in charge of the Alabama Department of Corrections, Kim Thomas, says he does not make decisions about charges against employees - that is down to the local district attorney.

"We do the initial investigation, and we turn our entire investigation over to them. Anything we have they are provided with," he explains.

Charlotte Morrison says there have been six convictions for criminal sexual misconduct at Alabama's Tutwiler prison in the last three years.

"We believe it's likely the tip of the iceberg. But in those six cases, only two of the accused actually spent any time in jail. One person spent one day in jail and the other six months."

Now, as a result of EJI's report on Tutwiler, there is an on-going federal Department of Justice investigation into the prison.

Meanwhile, Robert Chancey's mother-in-law, Brenda Singleton, is bringing up his cousin's baby. And when the baby starts asking questions about her parents, she believes honesty will be the best policy.

"We'll just have to tell her the truth - ain't no sense in sugar-coating it, because eventually she'll find out, so I'd rather tell her," says Brenda.

"Either me or her mother will tell her."

That is some years away. On a crackly phone from Tutwiler prison, Monica Washington says she is still dealing with the fall-out from the rape, and is seen by many inside the prison as responsible for what happened to her.

"I'm still getting looks from certain officers like 'I can't believe you did that', or whatever. I have to be on my Ps and Qs, always, when I am dealing with officers and inmates."

Listen to the full report on Assignment on the BBC World Service and Crossing Continents on BBC Radio 4. You can also download the report.