LOS ANGELES, April 14 (Xinhua) -- An expert's report released Tuesday by the American Civil Liberties Union (ACLU) described how brutal conditions in Los Angeles County's Central Jail "cause or contribute to violence and serious mental illness" there.

    The ACLU demanded that Los Angeles County swiftly implement changes to prevent unnecessary deaths or serious injuries in the jail.

    The report comes as Los Angeles County investigates the death of John Horton, 22, who was found hanging from a noose in his cell on March 30 after spending more than a month in Men's Central Jail following his arrest on a drug possession charge.

    The ACLU also released a letter from a witness detailing the events leading up to the death of Horton, who was held in solitary confinement in a dimly lit, windowless, solid-front cell the size of a closet. His body was already stiff by the time security staff discovered it.

    "Men's Central Jail is so grossly overcrowded, dangerous and dungeon-like that it puts intolerable stress on the jailed as well as the jailers," said Margaret Winter, associate director of the ACLU National Prison Project.

    Dr. Terry Kupers, a national expert on correctional medical health care, detailed intolerable conditions inside Men's Central Jail in Los Angeles in a 50-page report.

    "A prisoner cannot move more than a few feet away from a neighbor, and lines form at the pay telephones and the urinals. Likewise, when four men are crowded into the small cells I observed, there is barely enough room for one man to get off his bunk and head for the urinal," Kupers said.

    "In the cells I viewed, there are no chairs and no desks, so sitting or lying on one's bunk are the only options. With tough men crowded into small spaces and forced to lie on their bunks or wait in lines, altercations are practically inevitable," the expert said.

    When 150 or more prisoners are crowded into a room that has little space beyond what is taken up by the row of bunk beds they sleep in, there is little room for men to move without bumping into each other, and it is impossible for the officer assigned to supervise the dormitories to actually see what is going on, he said.

    Therefore, he added, beating and raping occurred in the cell.

    Although it is always difficult to prove that custodial abuse has occurred, the claims by prisoners at the Los Angeles County Jail are so widespread and the reports of abuse so consistent that it seems very likely there is an unacceptably high incidence of custodial abuse, Kupers said.

    "Multiple prisoners have told me about the abuse they have undergone or witnessed, and most say it is disproportionately directed at prisoners with serious mental illness," Kupers said.

    Kupers asserted that idleness and massive overcrowding at the jail leads to violence, victimization, custodial abuse and ultimately psychotic breakdown even in relatively healthy people, as well as potentially irreversible psychosis in detainees with pre-existing illness.

    Kupers also said mental health staff at the jail routinely fail to diagnose prisoners with serious mental illness, and downgrade the diagnoses of many who have long-established and well-documented maladies.

    These practices conceal the massive numbers of seriously mentally ill detainees, while also resulting in the transfer of many to the general jail population where they are victimized, or to solitary confinement, where their condition dramatically deteriorates, he said.

    With 20,000 detainees, the Los Angeles County jail system is the largest in the U.S. The Los Angeles County Men's Central Jail is nearly 50 years old and currently houses an average of 5,000 detainees, most of whom are awaiting trial and have not been convicted.

    Kupers estimated that nearly half of them suffer from mental illness. The total prison and jail population in the U.S. has climbed to well over two million and it keeps on growing, he said in the report.

    Los Angeles County spends more than 50,000 dollars per year to house each detainee with mental illness. And many low-risk detainees remain in jail for months simply because they are too poor to make bail.

    Adopting a comprehensive pre-trial release program for these detainees by making use of electronic monitoring or other close supervision would reduce the extreme overcrowding in the county's jails and free up millions of dollars for increased mental-health services without any risk to public safety, according to the report.

    "We call on the county to review the toxic conditions, abuse and overcrowding documented in Dr. Kupers' report, and that contributed to the tragic death of John Horton," said Melinda Bird, senior counsel for the ACLU of Southern California.

    "The county spends one billion dollars per year on its jails. Some of these funds must be diverted to new, more cost-effective programs that will reduce recidivism and end the criminalization of mental illness -- a cycle of incarceration that ensnares thousands of detainees with mental disabilities every year," Bird said.