HUNTSVILLE (AP) — With four months still remaining, 2012 is already the deadliest year in more than a decade in Texas prisons.

The Texas Department of Criminal Justice has reported 10 homicides this year, up from only three in 2011. There were five in 2010 and just one in 2009, according to agency figures.

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“It’s definitely jumped out at us,” Bruce Toney, the agency’s inspector general, said of the increase. “It definitely has not been an average year.”

The homicides don’t appear to be connected and have been scattered throughout the 111-prison system. The reason for the surge, the highest number in 15 years, is uncertain, Toney said.

He described the nature of the deaths in most cases as the result of “hands and feet kicking” and not a question of inmates armed with contraband weapons. More than half of the fatal attacks were committed in cells and involved altercations between cellmates, making it difficult to prevent.

“It’s a situation where they have some kind of disagreement and it results in a death,” he said. “Inside a prison cell, everything is metal so that leaves the potential for injuries if someone gets knocked down.”

“Unfortunately, offenders serving prison sentences can become aggressive and act out violently against not only staff but also other offenders,” prison department spokesman Jason Clark said. “The agency is committed to the safety of all offenders incarcerated within TDCJ.”

This year’s homicide total is a far cry from the wave of violence that swept a much smaller Texas corrections department in the 1980s. In 1985, 27 inmates were killed and hundreds of others hurt in attacks at a time when Texas prisons housed only about one-fourth of the more than 150,000 convicts now incarcerated. Since then, Texas spent more than $1 billion in prison construction and now has the nation’s largest state prison system.

A classification system implemented in the late 1980s to pair inmates with similar backgrounds eased the violence and some of the same procedures are still used today. For example, the difference in age of inmates sharing a two-person cell must be within nine years, their weight within 40 pounds. Medical restrictions are considered as well as any past incidents involving the pair. Race or ethnic origin is not a factor.

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Still, the slayings count for 2012 is the highest since 10 were reported in 1997.

“One thing we look at in housing assignments is did we put a bad guy in with a white-collar criminal or whatever,” Toney said. “The housing appears right, the classification appears right. … They’ve just been bad individuals locked up together in a cell.”

As a result, none of the cases “has really been a ‘whodunit,’ ” he said. “Almost in all of them, they’ve told corrections officers or us that they’ve done it. The instances we’ve had, there hasn’t been any doubt.”

A prisoner accused in a slaying could face a capital murder charge if he’s already serving a life term or 99 years. The decision on charges rests with the district attorney in the county where the death occurred or with the prison agency’s special prosecution unit.

In the most recent slaying, Elasko Thomas, an East Texas man sentenced two years ago to life in prison for kidnapping and aggravated sexual assault, was killed Aug. 7 at the Robertson Unit northeast of Abilene. Cellmate Michael Deloach is accused of killing him during an altercation, and is a year into a 40-year term for robbery.

None of the deaths has occurred in units where the agency is experiencing chronic difficulties filling corrections officer vacancies.

Only the Middleton Unit, a transfer unit also near Abilene, has been the scene of more than one homicide. Authorities said an inmate died of injuries suffered in a fight with another prisoner in a dayroom, and the other slaying was the result of a fight in a dormitory area.

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