The body of an Oklahoma death row inmate, who died after a botched execution in April, was returned to his family but two organs were missing.

This June 29, 2011 file photo provided by the Oklahoma Department of Corrections shows Clayton Lockett. Oklahoma prison officials halted the execution of Lockett Tuesday, April 29, 2014,  after the delivery of a new three-drug combination failed to go as planned. Oklahoma Gov. Mary Fallin said Lockett had an apparent heart attack more than 40 minutes after the start of the execution. (AP/Oklahoma Department of Corrections)

Oklahoma prison officials halted the execution of Clayton Lockett Tuesday, April 29, 2014, after the delivery of a new three-drug combination failed to go as planned. (AP/Oklahoma Department of Corrections)

Amy Elliott, a spokeswoman for the Oklahoma Medical Examiner’s Office, told Tulsa World that it’s not unusual that the Dallas County Medical Examiner’s Office kept Clayton Lockett’s heart and larynx for testing as it tries to establish his official cause of death.

“It allows further testing, but it also allows the family to go ahead and bury or cremate their loved ones,” Elliott told the newspaper.

“Oklahoma law reads that the Office of the State Medical Examiner can retain any kind of tissue or samples indefinitely,” Elliott added to the Associated Press. “And my understanding is it can be the same in Texas.”

The body of the man, who was was convicted of killing a 19-year-old woman, was brought to the Oklahoma Medical Examiner’s Office in May from the Dallas County office in Texas. This latter examiner’s office was brought on to the case by Oklahoma Gov. Mary Fallin to conduct an independent autopsy. Afterward, Lockett’s body was given to his family, which is also having an autopsy conducted.

Shortly after the new three-drug lethal injection system was pumped into Lockett’s vein on April 29, it was clear something was not going correctly. Officials stopped the drugs and could not start again, because they did not having another dose and found no other suitable veins, already taking nearly an hour to find one vein that collapsed in the initial administering of the drugs.

Lockett was said to have suffered an apparent heart attack 10 minutes after the execution was halted.

Elliot told Tulsa World that her office, not the Dallas County office, will make the official determination for Lockett’s cause of death. The Oklahoma office will consider the Dallas County office’s report in its own investigation though.

In this April 15, 2008 file photo, the gurney in the execution chamber at the Oklahoma State Penitentiary is pictured in McAlester, Okla. Attorney General Scott Pruitt's office filed court documents saying it wouldn't object to a 180-day stay of execution being sought by attorneys for inmate Charles Warner while the investigation is underway. Warner was scheduled for execution on the same night last week as Clayton Lockett in what would have been the state's first double execution since 1937. But Lockett's vein collapsed during his lethal injection. (AP)

The gurney in the execution chamber at the Oklahoma State Penitentiary is pictured in McAlester, Okla. Attorney General Scott Pruitt’s office filed court documents saying it wouldn’t object to a 180-day stay of execution being sought by attorneys for inmate Charles Warner while the investigation into Lockett’s cause of death is underway. Warner was scheduled for execution on the same night as Clayton Lockett. (AP)

“They send all their information to us. They don’t determine cause and manner. What they do is give their opinion. … We will make the determination of cause and manner,” Elliott told the newspaper.

After this incident, the Oklahoma Court of Criminal Appeals agreed to a six-month stay of execution for another death row inmate while the investigation into botched lethal injection continues.