Cody Hiland, prosecuting attorney for Arkansas' 20th Judicial District, said that the FBI's Little Rock field office had agreed to help his office gain access to a pair of locked devices owned by two of the suspects in the slayings of Robert and Patricia Cogdell.

It was not immediately clear whether the FBI planned to use the same method it used to access data on Syed Rizwan Farook's phone. Calls to the FBI's Little Rock field office were not immediately returned. An FBI spokesman in Washington declined to comment.

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The couple were killed in their home just outside Little Rock in July, according to the Associated Press. Four suspects, ages 14 to 18, have been charged in the killings, Hiland said.

Prosecutors asked for a delay in the trial of 18-year-old Hunter Drexler on Tuesday, less than 24 hours after the FBI said it had successfully gained access to an iPhone 5c that Farook used.