The defense in the trial of Valentino “Tino” Bagola tried Friday to bolster the confession from the father of two children slain on the Spirit Lake Reservation and sought to discredit Bagola’s confession.

The points were made during cross-examination of an FBI agent who took part in the interrogations of both men concerning the stabbing deaths of siblings Destiny Shaw and Travis DuBois Jr. in May 2011.

At first the children’s father, Travis DuBois Sr., was suspected of murdering both children and raping the girl.

After receiving DNA evidence in July 2012, however, the FBI shifted the focus of its investigation to Bagola, the nephew of the children’s mother, who was indicted for the murders and rape.

In questioning by the defense, Special Agent Brian Cima of the FBI acknowledged that the children’s father was a logical suspect at the outset of the investigation for several reasons.

DuBois was responsible for the children’s care during the three days leading up to the discovery of their bodies on May 21, 2011, and had been in the house most of that time, Cima agreed.

Also, the agent acknowledged, DuBois had been suspected because he was binge drinking during the period in question, and had a history of violent behavior and sometimes was abusive when he drank.

Public Defender Christopher Lancaster also asked a series of questions suggesting a less-than-thorough crime scene investigation that led to the charges against Bagola.

For instance, he got Cima to admit that the FBI didn’t perform tests to see whether water in a cleaning bucket in the DuBois home contained trace amounts of blood.

Similarly, Cima said, the FBI didn’t test to see whether blood not visible to the eye had spattered walls or other surfaces.

Both children suffered multiple stab wounds, and the room where their bodies were found was bloody, according to witnesses.

Lancaster suggested that DuBois, home much of the time between when the children were last seen alive and when their mother found their bodies, could have cleaned up the home.

“So where did the blood go?” Lancaster asked Cima.

“I don’t know,” the agent said.

In follow-up questioning by prosecutor Chris Myers, Cima said it didn’t appear that the bedroom had been cleaned. A bloody footprint outside the room apparently was lifted by a first responder, according to earlier testimony.

Cima also said, in response to a series of Lancaster’s questions, that DuBois made a number of self-incriminating statements to another FBI agent a few days after his children’s bodies were found.

Among other things, DuBois told the agent he “lost it” because the two children were jumping on their bed after he had told them to stop, and they were “talking back” to him, Cima said.

In follow-up questioning by Myers, however, Cima said the FBI was unable to corroborate DuBois’ confession, but had retrieved knives from locations Bagola provided in his confession, among other details.

Directing Cima’s attention to a meeting Bagola requested with the FBI after he was indicted in July 2012, and in which he asked how long a possible prison sentence could be, the agent agreed that the context for the remarks was that the defendant had questions about a document called a “detainer” that kept him in custody.

Prosecution testimony, including more forensic experts, will continue Monday. Lawyers expect testimony in the trial in U.S. District Court to conclude next week.