Prosecutors assigned to the case involving the death of Adrian Peterson's 2-year-old son are expected to ask a Lincoln County grand jury to consider more serious charges against the man charged in connection with the boy's killing,

Joseph Robert Patterson, 27, already faces charges of aggravated assault and aggravated battery in the slaying of Tyrese Robert Ruffin, who died after being hospitalized with severe head injuries suffered while he was under Patterson's care at his South Dakota home. Patterson was the boyfriend of the child's mother.

Sioux Falls district attorney Tom Wollman told NFL.com he is now reviewing the autopsy and other reports before formally seeking the upgraded charges.

Meanwhile, several other media outlets have reported the man identified as having raised the boy says he's "sick and tired of people feeling sorry for NFL star Peterson, who openly admits he met the boy for the first time as he lay hospitalized in a coma.

Bobby Ruffin told the media he only recently learned Peterson, and not he, was the boy's biological father. After the child passed away on Friday, Ruffin took to Twitter to exalt "so tired of this poor Adrian Peterson sh*t. Let me blow all your minds. The boy who died was my son."

"Yes A.P. he was the biological father but I raised him and he carried my name. Tyrese Robert Ruffin. I don't blame AP for not really caring cuz him and I both found out recently who the biological father was. AP met my son for the first time yest when my son was already in coma. I was here today when we pulled the plug, not him. He was happily practicing and has no problem playing on Sunday."