"I can not understand a situation worse than that of a father who has to testify against his son in such a serious matter," attorney Ralph Fernandez told CNN on Wednesday.
"It goes against everything we represent as a people in this country: dividing the home."
Howell "Trai" Donaldson III, 24, was arrested last week and charged with killing four people, apparently at random, in the Seminole Heights neighborhood in October and November.
Anthony Naiboa, Monica Hoffa, Benjamin Mitchell and Ronald Felton were shot dead in separate incidents when they walked alone at night.
The killings terrorized residents and sparked fears of a serial killer as police swarmed through the area waiting for clues to identify a suspect and stop attacks.
A motion filed Wednesday by the Hillsborough County state attorney's office Andrew Warren said Donaldson's father, also called Howell, refused to answer questions ̵
Warren told CNN that the parents received citations and were granted immunity from anything they say was used against them. But they stopped answering questions during a meeting with the researchers. The judge will decide if there are reasons for a hearing to show the cause, which will probably happen next week, according to the prosecutor.
& # 39; Indirect criminal contempt & # 39;
"Mr. Donaldson refused to answer any questions related to the investigation of his son's participation, Howell Emanuel Donaldson III, in the death of Benjamin Mitchell, Monica Hoffa, Anthony Naiboa and Ronald Felton, and They refused to answer any questions related to your child's background, developmental history, mode of transportation, possession and ownership of weapons, and the state of mind, "the motion of order to show the stated cause.
"In refusing to answer, Mr. Donaldson did not invoke any legal privilege or privilege derived from the Constitution of Florida or the United States." Mr. Donaldson's refusal to testify in the procedure described above, despite having received a judicial authorization judicial summons, constitutes an indirect criminal contempt of this Honorable Court ".
Fernandez questioned why prosecutors would take an "extraordinary step," given the evidence they claim to have against young Donaldson.
The lawyer told the station described as the "perfect family", were interviewed separately and refused to answer questions about his son's mental health, his mood before the murders and whether he was in psychiatric care.
"Every time the answer was obtained, I'm not going to answer that question," Fernandez said.
The couple has said they are devastated and incredulous that their son could have done such a thing.
He faces four counts of murder and could face the death penalty if convicted. Donaldson has resigned from a formal hearing on his pre-trial detention, and will be held without bail on charges, according to a court order issued Monday.
& # 39; Why? Why?
Speaking at a press conference with lawyers last week, Donaldson's parents said they had not seen their son since his arrest but wanted to offer his love and support .
"He needs to know that we love him and support him and we have to see him," said Rosita Donaldson.
"We believe in him and us". we are here for him. "
] Howell Donaldson III graduated from St. John's University in New York in January 2017 and was a walk-on for the men ketball team during the 2011-12 season, according to Brian Browne, executive director of university relations
The family's lawyers declined to comment on whether they had seen the surveillance video of the suspect that the police released weeks ago, while the parents spoke emotionally about their family and the families of the victims.
"We just want to say that we love our son, we support our son, and we pray the strength for the family members and we only ask that they do the same for us and pray for us because we are all devastated," said Rosita Donaldson
He said that they had prayed for the families of the victims and hoped that those families would return the effort
. " (We feel) devastation for the family, and that's when it started. I prayed for those families when it began, "said Rosita Donaldson." And then when they arrested my son, devastation because I love my son, and I was incredulous that this was happening to our family, and we asked why? "
 Rosa Flores and Kevin Conlon of CNN contributed to this report.