News On 6 has new information about the murder of five members of the Bever family last month in Broken Arrow.
Police say one of the suspects told police they kept the plans for the killing saved on a flash drive.
Investigators believe teen brothers Robert and Michael Bever used hatchets and knives to kill their parents, David and April, and three siblings in the family home.
Documents show police found blood-stained clothing in the area where they arrested the Bever brothers. Police asked for search warrants for the home and for blood samples and footprints of both suspects.
Special Coverage: Bever Family Murders
With each new detail that comes to light, the already tragic case becomes more horrific.
Keeping a plan of the killings on a flash drive signifies to homicide investigators the murders were not a spontaneous act but one planned in advance, officers say.
Documents say officers found bloody footprints all over the floor and several of them were made by bare feet, some belonged to the victims and some to the suspects. Officers wanted footprints taken of Robert and Michael Bever to figure out who made which prints, documents say.
Detectives also asked a judge for blood samples from the brothers for DNA comparison to the scene.
When officers searched the home with a warrant, they were looking for knives, machetes and swords, along with computers, cell phones, flash drives or documents that would contain plans of a mass homicide, along with military style or tactical clothing, masks, gloves or blood-stained clothing.
An attorney for the 2-year-old girl who was not injured and the 13-year-old girl who survived, says they are in a loving, safe home now and they are working to get guardians appointed for the girls. The 13-year-old survivor will be the key witness in the case as it moves forward.
Public defenders have been appointed to represent the two brothers, Robert and Michael, who each have been charged with five counts of first-degree murder and one count of assault with intent to kill. Not guilty pleas have been entered on behalf of both teenagers.
The judge has said the defense attorneys can keep private any information dealing with them hiring experts or investigators on behalf of the Bever brothers so their defense strategy is not compromised.
On Thursday, the City of Broken Arrow released 49 pages of documents, including the computer-generated notes a 911 dispatcher made during the call for help.
A Tulsa County judge decided this week the 911 call was an open record, but he stopped short at allowing the audio to be released.