An arrest affidavit did not include a narrative or further details Thursday.
Green often walked down the street to a gas station convenience store, where he would buy three or four energy drinks for himself and his family members, neighbors and workers at the store said.
On his walks, he chatted with his neighbors, who described him as friendly, but “off.” A neighbor with young children said he often spoke of the infant he is now accused of killing.
Police said the suspect and the victims were relatives.
Neighbor Sabrina White said Daniel Green and Rebecca Cizek were brother and sister, and Sallie Green was their mother. Katherine Cizek and the baby were Rebecca Cizek's children, she said.
On Facebook, Rebecca Cizek shared photos and videos of her baby boy, bouncing in a seat, playing with the leaves on a tree. Rebecca Cizek formerly worked at Sonic Drive-In according to public records and her Facebook profile.
In one photo, Daniel Green is affectionately holding the baby boy up for the camera. The same string of pictures shows Katherine playing with the baby.
Katherine Cizek, who went by Kat, was ready to start her sophomore year at Del City High School on Monday, said Midwest City-Del City School District spokeswoman Stacey Boyer.
On a May 2 Facebook photo depicting the teenager smiling with hair piled high on top of her head, Daniel Green wrote to his niece.
“There's my lovely, almost 17 year old nieace, I call her rugla,” Green wrote. “but her real nick name is khat, I hope she finds her true love or at least who it is.”
On his relatives' pages, he often wrote supportive messages.
“hey baby sis, I see your proud of your perkily whites, love you!!” he wrote April 23 on Rebecca Cizek's page.
Green's Facebook page is dedicated almost entirely to former Disney star Selena Gomez.
In the Sunny Pointe neighborhood where the victims were found, a woman walking her dogs Thursday stopped outside the home to ask reporters what was going on.
She was horrified to learn family members had been killed.
“Why would anyone do that?” the woman asked.
Staff Writer Bryan Dean, News Research Editor Linda Lynn and Assistant News Research Editor Melissa Hayer