COLUMBIA, S.C. (AP) –UPDATE 8 p.m., – Saturday

The Latest on four inmates authorities said were killed by two other prisoners in South Carolina (all times local):

Autopsies on four inmates found dead inside a cell in a South Carolina prison say they were all strangled and were killed within 30 minutes of each other.

Richland County Coroner Gary Watts said in a statement that 52-year-old John King was choked with an electrical cord on Friday morning at Kirkland Correction Intuition in Columbia.

Watts says the killers of 44-year-old William Scruggs strangled him while pressing on his chest, while 35-year-old Jason Kelley and 56-year-old Jimmy Hamm were also strangled.

The coroner says all four inmates died between 10 a.m. and 10:30 a.m. on Friday.

Two inmates serving life sentences – each for killing a mother and her child – have been charged with four counts of murder in the killings.  Prison officials say they are being held in the system’s highest security area.UPDATE 11:30a.m., Saturday

COLUMBIA, SC – Two convicts who are each serving a life sentence for killing a mother and her child have been charged with murdering four fellow inmates at a South Carolina prison.

Arrest warrants released early Saturday say Denver Simmons, 35, and Jacob Philip, 25, lured each inmate into a cell at Kirkland Correctional Institution in Columbia on Friday morning. Sommer Sharpe with the SC Department of Corrections said the inmates were found deceased in a housing unit at 10:35 a.m. The warrants released Saturday say the men worked together to choke all four inmates. Two of the victims were also beaten and stabbed with a broken broomstick.

One of the four men killed was charged with crimes in Darlington County. Sharpe identified the deceased as John King, Jason Kelley, Jimmy Ham, and William Scruggs.Kelley was serving time for burglary charges, grand larceny, and assault and battery of a high and aggravated nature, all which occurred in Darlington County, an inmate report says.

An inmate report also says Kelley was sentenced to 15 years for assault and battery of a high and aggravated nature in Cherokee County. King was in the prison for several crimes including larceny charges, burglaries, vehicle thefts and breaking and entering in Greenville County, according to the inmate report. Scruggs had ties to Anderson County and the inmate report says he was serving a life sentence for murder and a life sentence for first degree burglary along with time for kidnapping and a weapons violation.

SLED is the lead investigating authority along with the Richland County Coroner’s Office. The agencies will be assisted by the South Carolina Department of Corrections Police Services Division.

The arrest warrants gave no reason for the attack or how long the killings took. Prison officials are investigating the attack and have not commented. The warrants say there is video. It wasn’t known if the inmates had lawyers.